Representation classes now only accept Quantity to simplify API and behavior of low-level frame classes
Updated API tests
Provide backward-compatibility layer in frames
Fix backward-compatibility layer
Add back APE5 tests but simply update them
Disallow non-Quantity input for CartesianRepresentation
Move up deprecation message
Fix test failures resulting from changes to CartesianRepresentation
Merge pull request #26 from astrofrog/no-string-frame-repr

Require representation input to be Quantity, and backward-compatibility layer