Small improvements to ResidueRange, AtomPosition, and ResidueNumber; added a few useful methods. No bug fixes.

git-svn-id: file:///home/svn-repositories/biojava/biojava-live/trunk@10057 7c6358e6-4a41-0410-a743-a5b2a554c398
Forgot to commit AtomPositionMap's test; adding it now.

git-svn-id: file:///home/svn-repositories/biojava/biojava-live/trunk@10058 7c6358e6-4a41-0410-a743-a5b2a554c398