(No Issue): Refactor branchhealthconfig module to be named 'config' and BranchHealth module to be named 'branchhealth'.
Issue #3: Add argument for branch deletion option to parser arguments.
Issue #3: Move all options into a specific object for easier transport among functions.
Issue #3: Extract isoDateComparator into util module for clarity and cohesiveness.
Issue #3: Add delete branches as an option in BranchHealthOptions and utilize the option when processing branches.
Issue #3: Correct an error caused by not interpreting the number of days in an option set as an integer.
Issue #3: Extract functionality for deleting branches into a separate function.
Issue #3: Add functionality to delete branches that are 'unhealthy'.
Issue #3: Add a BranchManager class to handle branches within gitbranchhealth and an associated test suite.
(No Issue): Add python-dateutil to prevent crashing on Travis CI.
Issue #3: Move branch management functions out of branchhealth module and into manager module.
Issue #3: Add a test for BranchManager.getBranchMap().