Merge pull request #5 from Cadair/coordinates-framework

Subclass TimeFrameAttribute to allow 'now' as a value.
Merge pull request #6 from Cadair/coordinates-framework

Change the transforms to realize the target frame class.
Removed the '.' from an import to test in the interpreter.
Merge branch 'coordinates-framework' of github.com:VaticanCameos/sunpy into coordinates-framework

Conflicts:
	sunpy/coordinates/frames.py