Fixes issue 1018.  Creates a new package-protected java.util.Comparators utility class to provide the natural order Comparator, corrects Arrays.binarySearch when called with a null Comparator, and adds Collections.binarySearch.  Test cases provided for the new functionality.

Patch by: sandymac, jat
Review by: mmendez



git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@1027 8db76d5a-ed1c-0410-87a9-c151d255dfc7