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, 43 insertions, 0 deletions

diff --git a/test/scaladoc/run/implicits-var-exp.scala b/test/scaladoc/run/implicits-var-exp.scala
new file mode 100644
index 0000000000..16569fe3c2
--- /dev/null
+++ b/test/scaladoc/run/implicits-var-exp.scala
@@ -0,0 +1,43 @@
+import scala.tools.nsc.doc.model._
+import scala.tools.nsc.doc.model.diagram._
+import scala.tools.partest.ScaladocModelTest
+
+object Test extends ScaladocModelTest {
+
+  override def code = """
+        package scala.test.scaladoc.variable.expansion {
+          /**
+           * Blah blah blah
+           */
+          class A
+
+          object A {
+            import language.implicitConversions
+            implicit def aToB(a: A) = new B
+          }
+
+          /**
+           * @define coll collection
+           */
+          class B {
+            /**
+             * foo returns a $coll
+             */
+            def foo: Nothing = ???
+          }
+        }
+    """
+
+  // diagrams must be started. In case there's an error with dot, it should not report anything
+  def scaladocSettings = "-implicits"
+
+  def testModel(rootPackage: Package) = {
+    // get the quick access implicit defs in scope (_package(s), _class(es), _trait(s), object(s) _method(s), _value(s))
+    import access._
+
+    val base = rootPackage._package("scala")._package("test")._package("scaladoc")._package("variable")._package("expansion")
+    val foo = base._class("A")._method("foo")
+
+    assert(foo.comment.get.body.toString.contains("foo returns a collection"), "\"" + foo.comment.get.body.toString + "\".contains(\"foo returns a collection\")")
+  }
+}
\ No newline at end of file