Merge main(...) and runMainAndExit(...).

Commit 917a88fad06ce108a596a8fdb4607b1a2fbb3f3e changed the
visibility of runMainAndExit from public to private. The method
is only called by main and therefore runMainAndExit is not needed
anymore.
Fix JavaDoc.
Merge pull request #709 from stefanbirkner/junitcore

JUnitCore
Fix path to JavaDoc style sheet.
Rewrite JavaDoc of ExcludeCategories.createFilter(Class<?>...).

Remove internal details of the created filter and describe its behaviour instead.
Rewrite JavaDoc of IncludeCategories.createFilter(Class<?>...).

Remove internal details of the created filter and describe its behaviour instead.
Simplify JavaDoc of RunNotifier.fireTestFinished(...).
Remove JavaDoc reference to test class.

The test class is no available by JavaDoc.
Clean up JavaDoc of JUnit38ClassRunner.getAnnotations(...).

Remove empty return and add description of the parameter.
Merge pull request #710 from stefanbirkner/javadoc

Fix JavaDoc errors and warnings.
Re #686: Added thread safety warnings to @Test javadoc.
Merge pull request #715 from russellsantos/issue686

Re #686: Added thread safety warnings to @Test javadoc.
Delete .cvsignore files, because we're using Git now.
Merge pull request #721 from stefanbirkner/cvsignore

Delete .cvsignore files, because we're using Git now.
extract validators