ri support for superclass indicators - UPDATES MARSHAL FORMAT
Add support for documenting class/module extensions

--HG--
rename : lib/rdoc/include.rb => lib/rdoc/extend.rb
rename : test/test_rdoc_include.rb => test/test_rdoc_extend.rb
Fix accidentally-committed keyword changes and generated files.
Finish up documentation for class/module extensions.

--HG--
rename : lib/rdoc/generator/template/darkfish/_sidebar_includes.rhtml => lib/rdoc/generator/template/darkfish/_sidebar_extends.rhtml
Updated Manifest for #115
find_superclass_method is now lazy.
fix for ri driver -- RDoc::Markup::List does not have a #concat method.
Fixes for tests; I had forgotten how superclass_method worked.
Merge branch 'master' into ri_superclass
switch to ivars from assignment accessors
Merge branch 'master' into ri_superclass
Merge pull request #130 from zzak/d96d571

test_rdoc_markup_to_html.rb: s/gem_url/gen_url
Updated History for #130
Merge pull request #118 from ged/extend-doc-feature

Add documentation for 'extend' modules
Added tests for functionality from #118

This fills in several tests that weren't written in the pull request,
including tests for Marshal format compatibility.
Expanded Context#each_ancestor comment

The first commit didn't explain why the function exists.  This update is
a best guess since I didn't actually track down what problem it solved.
Added ri support for extends

This finishes missing functionality from #118.
Merge pull request #116 from erikh/ri_superclass

Add indication that a method calls super
Complete 646194af

I fail at git, this commit finishes my previous work.
Minor updates for #118

Changed uses_superclass to calls_super which is a bit more descriptive
of what the method means and also reads better when used.

Altered AnyMethod's Marshal format to store the uses_super flag instead
of the found method.  This reduces the size of the stored data slightly
and allows superclass lookup by ri across stores (for super across
libraries).

Renamed find_superclass_method to just superclass_method.

RDoc::NormalClass#ancestors now returns the entire ancestors list.  The
old behavior exists as direct_ancestors.  This allowed a simplification
of superclass_method that also fixed a bug when the superclass method
existed more than one level away or in an included module.

RDoc::NormalClass#each_ancestor now returns an Enumerator when no block
is given.  (This was part of a refactor attempt that didn't work out.)

Simplified parse_statements test for uses_super from a functional test
to a unit test.