change java compiler to only produce one java file


git-svn-id: http://protobuf.googlecode.com/svn/trunk@548 630680e5-0e50-0410-840e-4b1c322b438d
1, Add comments for include<algorithm> we added for min/max on VS2013. 2, Add #if/#endif to wrap #undef


git-svn-id: http://protobuf.googlecode.com/svn/trunk@549 630680e5-0e50-0410-840e-4b1c322b438d
Change java descriptor back to private


git-svn-id: http://protobuf.googlecode.com/svn/trunk@550 630680e5-0e50-0410-840e-4b1c322b438d