Cleanup/Refactor: Removed unused and organized imports. Replaced hardcoded Order States for enum-like values.

Currently order states are directly strings, with irregular capitalization.
In the future it might be better to just have this field store a byte value, and to represent
it in the user interface we can have a map that gives us the right representation, should also
be easier to internationalize the text this way as there'd be only one place to maintain
the corresponding english names for the order states.

Refactored get_order() method to get rid of unnecessary code repetition. DRY principle.
Merge pull request #169 from gubatron/master

Cleanup/Refactor: Removed unused and organized imports. Order State enum, DRY principle

This is awesome! Thanks.