Scaladoc class diagrams part 1

This commit contains model changes required for adding class diagrams
to scaladoc. It also contains an improved implicit shadowing
computation, which hides the shadowed implicitly inherited members
from the main view and gives instructions on how to access them.

This is joint work with Damien Obrist (@damienobrist) on supporting
diagram generation in scaladoc, as part of Damien's semester project
in the LAMP laborarory at EPFL.

The full history is located at:
https://github.com/damienobrist/scala/tree/feature/diagrams-dev

Commit summary:

 - diagrams model
   - diagram settings (Settings.scala, ScalaDoc.scala)
   - diagram model object (Entity.scala, Diagram.scala)
   - model: tracking direct superclasses and subclasses,
     implicit conversions from and to (ModelFactory.scala)
   - diagram object computation (DiagramFactory.scala, DocFactory.scala)
   - capacity to filter diagrams (CommentFactory.scala,
     DiagramDirectiveParser.scala)
   - diagram statistics object (DiagramStats.scala)
   - delayed link evaluation (Body.scala, Comment.scala)
   - tests

 - improved implicits shadowing information
   - model shadowing computation (ModelFactoryImplicitSupport.scala,
     Entity.scala)
   - html generation for shadowing information (Template.scala)
   - tests

Also fixes an issue reported by @dragos, where single-line comment
expansion would lead to the comment disappearing.

Review by @kzys, @pedrofurla.

Adapted to the new model and fixed a couple of problems:
 - duplicate implicit conversions in StringAdd/StringFormat
 - incorrect implicit conversion signature (from X to X)

Conflicts:

	src/compiler/scala/tools/nsc/doc/Settings.scala
	src/compiler/scala/tools/nsc/doc/html/page/Template.scala
	src/compiler/scala/tools/nsc/doc/model/Entity.scala
	src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala
	src/compiler/scala/tools/nsc/doc/model/ModelFactoryImplicitSupport.scala

1 files changed, 72 insertions, 0 deletions

diff --git a/test/scaladoc/resources/implicits-ambiguating-res.scala b/test/scaladoc/resources/implicits-ambiguating-res.scala
new file mode 100644
index 0000000000..6ed51366cb
--- /dev/null
+++ b/test/scaladoc/resources/implicits-ambiguating-res.scala
@@ -0,0 +1,72 @@
+/**
+ *  Test scaladoc implicits distinguishing -- supress all members by implicit conversion that are shadowed by the
+ *  class' own members
+ *
+ *  {{{
+ *     scala> class A { def foo(t: String) = 4 }
+ *     defined class A
+ *
+ *     scala> class B { def foo(t: Any) = 5 }
+ *     defined class B
+ *
+ *     scala> implicit def AtoB(a:A) = new B
+ *     AtoB: (a: A)B
+ *
+ *     scala> val a = new A
+ *     a: A = A@28f553e3
+ *
+ *     scala> a.foo("T")
+ *     res1: Int = 4
+ *
+ *     scala> a.foo(4)
+ *     res2: Int = 5
+ *  }}}
+ */
+package scala.test.scaladoc.implicits.ambiguating
+import language.implicitConversions // according to SIP18
+
+/** - conv1-5 should be ambiguous
+ *  - conv6-7 should not be ambiguous
+ *  - conv8 should be ambiguous
+ *  - conv9 should be ambiguous
+ *  - conv10 and conv11 should not be ambiguous */
+class A[T]
+/** conv1-9 should be the same, conv10 should be ambiguous, conv11 should be okay */
+class B extends A[Int]
+/** conv1-9 should be the same, conv10 and conv11 should not be ambiguous */
+class C extends A[Double]
+    /** conv1-9 should be the same, conv10 should not be ambiguous while conv11 should be ambiguous */
+class D extends A[AnyRef]
+
+class X[T] {
+  def conv1: AnyRef = ???
+  def conv2: T = ???
+  def conv3(l: Int): AnyRef = ???
+  def conv4(l: AnyRef): AnyRef = ???
+  def conv5(l: AnyRef): String = ???
+  def conv6(l: String)(m: String): AnyRef = ???
+  def conv7(l: AnyRef)(m: AnyRef): AnyRef = ???
+  def conv8(l: AnyRef): AnyRef = ???
+  def conv9(l: String): AnyRef = ???
+  def conv10(l: T): T = ???
+  def conv11(l: T): T = ???
+}
+
+class Z[T] {
+  def conv1: AnyRef = ???
+  def conv2: T = ???
+  def conv3(p: Int): AnyRef = ???
+  def conv4(p: AnyRef): String = ???
+  def conv5(p: AnyRef): AnyRef = ???
+  def conv6(p: String, q: String): AnyRef = ???
+  def conv7(p: AnyRef, q: AnyRef): AnyRef = ???
+  def conv8(p: String): AnyRef = ???
+  def conv9(p: AnyRef): AnyRef = ???
+  def conv10(p: Int): T = ???
+  def conv11(p: String): T = ???
+}
+
+object A {
+  implicit def AtoX[T](a: A[T]) = new X[T]
+  implicit def AtoZ[T](a: A[T]) = new Z[T]
+}