* System/String.cs: Fix String.Split(String[],int,StringSplitOptions)

	* System/String.cs: Fix String.Split(String[],int,StringSplitOptions)
	  so that:
	  - it properly obeys the 'count' parameter; Fixes #601772.
	  - "...".Split(new[]{"."}, 2, StringSplitOptions.RemoveEmptyEntries).Length==0
	  - "A..".Split (new String[] { "." }, 2, StringSplitOptions.RemoveEmptyEntries) == new[]{"A"}
	  - Remove duplicative array handling code by using List<String>.
	* Test/System/StringTest.cs: Add tests for #601772 (i.e. take
	  SplitStringChars(), change all the chars to Strings, and things
	  should work).

svn path=/trunk/mcs/; revision=158670