Merge pull request #1 from baratrion/master

verbose_name_plural for Currency
Added same currency conversion check.
incremented version number
Merge pull request #2 from huseyinyilmaz/master

Added same currency check
added convert_value function
fixed packaging
refactored and added celery task support
fixed broken import
bumped version
refactored with caching improvements
bumped version
reordered convert_value args