[SPARK-9855] [SPARKR] Add expression functions into SparkR whose params are simple

I added lots of expression functions for SparkR. This PR includes only functions whose params  are only `(Column)` or `(Column, Column)`.  And I think we need to improve how to test those functions. However, it would be better to work on another issue.

## Diff Summary

- Add lots of functions in `functions.R` and their generic in `generic.R`
- Add aliases for `ceiling` and `sign`
- Move expression functions from `column.R` to `functions.R`
- Modify `rdname` from `column` to `functions`

I haven't supported `not` function, because the name has a collesion with `testthat` package. I didn't think of the way  to define it.

## New Supported Functions

```
approxCountDistinct
ascii
base64
bin
bitwiseNOT
ceil (alias: ceiling)
crc32
dayofmonth
dayofyear
explode
factorial
hex
hour
initcap
isNaN
last_day
length
log2
ltrim
md5
minute
month
negate
quarter
reverse
round
rtrim
second
sha1
signum (alias: sign)
size
soundex
to_date
trim
unbase64
unhex
weekofyear
year

datediff
levenshtein
months_between
nanvl
pmod
```

## JIRA
[[SPARK-9855] Add expression functions into SparkR whose params are simple - ASF JIRA](https://issues.apache.org/jira/browse/SPARK-9855)

Author: Yu ISHIKAWA <yuu.ishikawa@gmail.com>

Closes #8123 from yu-iskw/SPARK-9855.

1 files changed, 12 insertions, 9 deletions

diff --git a/R/pkg/inst/tests/test_sparkSQL.R b/R/pkg/inst/tests/test_sparkSQL.R
index 7377fc8f1c..e6d3b21ff8 100644
--- a/R/pkg/inst/tests/test_sparkSQL.R
+++ b/R/pkg/inst/tests/test_sparkSQL.R
@@ -640,15 +640,18 @@ test_that("column operators", {
 
 test_that("column functions", {
   c <- SparkR:::col("a")
-  c2 <- min(c) + max(c) + sum(c) + avg(c) + count(c) + abs(c) + sqrt(c)
-  c3 <- lower(c) + upper(c) + first(c) + last(c)
-  c4 <- approxCountDistinct(c) + countDistinct(c) + cast(c, "string")
-  c5 <- n(c) + n_distinct(c)
-  c5 <- acos(c) + asin(c) + atan(c) + cbrt(c)
-  c6 <- ceiling(c) + cos(c) + cosh(c) + exp(c) + expm1(c)
-  c7 <- floor(c) + log(c) + log10(c) + log1p(c) + rint(c)
-  c8 <- sign(c) + sin(c) + sinh(c) + tan(c) + tanh(c)
-  c9 <- toDegrees(c) + toRadians(c)
+  c1 <- abs(c) + acos(c) + approxCountDistinct(c) + ascii(c) + asin(c) + atan(c)
+  c2 <- avg(c) + base64(c) + bin(c) + bitwiseNOT(c) + cbrt(c) + ceil(c) + cos(c)
+  c3 <- cosh(c) + count(c) + crc32(c) + dayofmonth(c) + dayofyear(c) + exp(c)
+  c4 <- explode(c) + expm1(c) + factorial(c) + first(c) + floor(c) + hex(c)
+  c5 <- hour(c) + initcap(c) + isNaN(c) + last(c) + last_day(c) + length(c)
+  c6 <- log(c) + (c) + log1p(c) + log2(c) + lower(c) + ltrim(c) + max(c) + md5(c)
+  c7 <- mean(c) + min(c) + minute(c) + month(c) + negate(c) + quarter(c)
+  c8 <- reverse(c) + rint(c) + round(c) + rtrim(c) + second(c) + sha1(c)
+  c9 <- signum(c) + sin(c) + sinh(c) + size(c) + soundex(c) + sqrt(c) + sum(c)
+  c10 <- sumDistinct(c) + tan(c) + tanh(c) + toDegrees(c) + toRadians(c)
+  c11 <- to_date(c) + trim(c) + unbase64(c) + unhex(c) + upper(c) + weekofyear(c)
+  c12 <- year(c)
 
   df <- jsonFile(sqlContext, jsonPath)
   df2 <- select(df, between(df$age, c(20, 30)), between(df$age, c(10, 20)))