[SPARK-1566] consolidate programming guide, and general doc updates

This is a fairly large PR to clean up and update the docs for 1.0. The major changes are:

* A unified programming guide for all languages replaces language-specific ones and shows language-specific info in tabs
* New programming guide sections on key-value pairs, unit testing, input formats beyond text, migrating from 0.9, and passing functions to Spark
* Spark-submit guide moved to a separate page and expanded slightly
* Various cleanups of the menu system, security docs, and others
* Updated look of title bar to differentiate the docs from previous Spark versions

You can find the updated docs at http://people.apache.org/~matei/1.0-docs/_site/ and in particular http://people.apache.org/~matei/1.0-docs/_site/programming-guide.html.

Author: Matei Zaharia <matei@databricks.com>

Closes #896 from mateiz/1.0-docs and squashes the following commits:

03e6853 [Matei Zaharia] Some tweaks to configuration and YARN docs
0779508 [Matei Zaharia] tweak
ef671d4 [Matei Zaharia] Keep frames in JavaDoc links, and other small tweaks
1bf4112 [Matei Zaharia] Review comments
4414f88 [Matei Zaharia] tweaks
d04e979 [Matei Zaharia] Fix some old links to Java guide
a34ed33 [Matei Zaharia] tweak
541bb3b [Matei Zaharia] miscellaneous changes
fcefdec [Matei Zaharia] Moved submitting apps to separate doc
61d72b4 [Matei Zaharia] stuff
181f217 [Matei Zaharia] migration guide, remove old language guides
e11a0da [Matei Zaharia] Add more API functions
6a030a9 [Matei Zaharia] tweaks
8db0ae3 [Matei Zaharia] Added key-value pairs section
318d2c9 [Matei Zaharia] tweaks
1c81477 [Matei Zaharia] New section on basics and function syntax
e38f559 [Matei Zaharia] Actually added programming guide to Git
a33d6fe [Matei Zaharia] First pass at updating programming guide to support all languages, plus other tweaks throughout
3b6a876 [Matei Zaharia] More CSS tweaks
01ec8bf [Matei Zaharia] More CSS tweaks
e6d252e [Matei Zaharia] Change color of doc title bar to differentiate from 0.9.0

1 files changed, 5 insertions, 3 deletions

diff --git a/docs/graphx-programming-guide.md b/docs/graphx-programming-guide.md
index 42ab27bf55..fdb9f98e21 100644
--- a/docs/graphx-programming-guide.md
+++ b/docs/graphx-programming-guide.md
@@ -10,7 +10,7 @@ title: GraphX Programming Guide
   <img src="img/graphx_logo.png"
        title="GraphX Logo"
        alt="GraphX"
-       width="65%" />
+       width="60%" />
   <!-- Images are downsized intentionally to improve quality on retina displays -->
 </p>
 
@@ -25,6 +25,8 @@ operators (e.g., [subgraph](#structural_operators), [joinVertices](#join_operato
 addition, GraphX includes a growing collection of graph [algorithms](#graph_algorithms) and
 [builders](#graph_builders) to simplify graph analytics tasks.
 
+**GraphX is currently an alpha component. While we will minimize API changes, some APIs may change in future releases.**
+
 ## Background on Graph-Parallel Computation
 
 From social networks to language modeling, the growing scale and importance of
@@ -86,7 +88,7 @@ support the [Bagel API](api/scala/index.html#org.apache.spark.bagel.package) and
 [Bagel programming guide](bagel-programming-guide.html). However, we encourage Bagel users to
 explore the new GraphX API and comment on issues that may complicate the transition from Bagel.
 
-## Upgrade Guide from Spark 0.9.1
+## Migrating from Spark 0.9.1
 
 GraphX in Spark {{site.SPARK_VERSION}} contains one user-facing interface change from Spark 0.9.1. [`EdgeRDD`][EdgeRDD] may now store adjacent vertex attributes to construct the triplets, so it has gained a type parameter. The edges of a graph of type `Graph[VD, ED]` are of type `EdgeRDD[ED, VD]` rather than `EdgeRDD[ED]`.
 
@@ -690,7 +692,7 @@ class GraphOps[VD, ED] {
 
 In Spark, RDDs are not persisted in memory by default. To avoid recomputation, they must be explicitly cached when using them multiple times (see the [Spark Programming Guide][RDD Persistence]). Graphs in GraphX behave the same way. **When using a graph multiple times, make sure to call [`Graph.cache()`][Graph.cache] on it first.**
 
-[RDD Persistence]: scala-programming-guide.html#rdd-persistence
+[RDD Persistence]: programming-guide.html#rdd-persistence
 [Graph.cache]: api/scala/index.html#org.apache.spark.graphx.Graph@cache():Graph[VD,ED]
 
 In iterative computations, *uncaching* may also be necessary for best performance. By default, cached RDDs and graphs will remain in memory until memory pressure forces them to be evicted in LRU order. For iterative computation, intermediate results from previous iterations will fill up the cache. Though they will eventually be evicted, the unnecessary data stored in memory will slow down garbage collection. It would be more efficient to uncache intermediate results as soon as they are no longer necessary. This involves materializing (caching and forcing) a graph or RDD every iteration, uncaching all other datasets, and only using the materialized dataset in future iterations. However, because graphs are composed of multiple RDDs, it can be difficult to unpersist them correctly. **For iterative computation we recommend using the Pregel API, which correctly unpersists intermediate results.**