The project helper impl - all the private methods that used to be in ProjectHelper.

I only did a small refactoring to change inner classes to static inner classes
and pass explicitely the parameters. This improve the compatibility with jikes,
gcj and possibly other compilers, and is ( IMHO ) cleaner.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@271781 13f79535-47bb-0310-9956-ffa450edef68