Fixed a dependency for manual non  'setup.py' install where 'pkg_resources.get_distribution('pint').version' would error out as it is not defined; __version__ is first assigned 'git describe' output, followed by get_distribution(...)' call and if that fails it defaults to “unknown”.
Fix for Issue #46, calling 'to_base_units' on Quality with Decimal magnitudes no longer throws a TypeError caused by attempting to multiply a float with Decimal. Further edge cases for other magnitude types might be required.
Added test cases for Issues 37 and 39
Merge branch 'issue-46-fix' of https://github.com/danielsokolowski/pint into develop
Merge branch 'issue-42-fix' of https://github.com/danielsokolowski/pint into develop
Updated CHANGES with 42 and 46