Issue #10: Remove getBranchPath() in favor of using git.Reference.path, and document some of the BranchManager methods.
Issue #10: Document remaining methods in manager.py for consistency.
Issue #10: Move sortBranchMap into BranchManager and showBranchHealth into BranchHealthApplication.
Issue #11: Add a test for branchDateComparator function.
Issue #11: Make all branchhealth-related operations member functions of the BranchHealthApplication class.
Issue #11: Refactor logging so that log output can be specified on the command line using the -v* option.
Issue #11: Remove useless splitBranchPath function, as it's no longer needed.
Issue #11: Make showBranchHealth take a parameter for the stream to output to, in the event that users wish to output somewhere other than standard out.