* System.CodeDom.Compiler/CodeGenerator.cs: Clear out the current member

	* System.CodeDom.Compiler/CodeGenerator.cs: Clear out the current member
	  when beginning Type generation.  This prevents "invalid"
	  `#endregion`s; if the CodeGenerator instance is reused for multiple
	  types, the last member of the first type has an EndDirective, then
	  the EndDirectvies will be generated before any members of the 2nd
	  type.  Don't do that.
	* Test/System.CodeDom.Compiler/CodeGeneratorTest.cs: Add some testing
	  for CodeRegionDirectives.

svn path=/trunk/mcs/; revision=155321