separate out the request for the z-coordinate from the calculation of the z-coordinate (found by Laura Hayes)
put the ability to pass in a z-corinate back into convert_hg_hcc, returning the 0.2 functionality
Changed the norm() method of GenericMap to an attribute.

This allows the user to overwrite it and customise it.
I have also changed the keyword parseing in MapCube.plot()
so that all kwargs are passed to imshow and kwargs to
mpl.animation.FuncAnimate can be passed in a dict in the ani_kwagrs
kwarg.
Merge branch '0.3_norm' into norm_fix
more comments on the code changes
added in another example of the conversion
amended example
Merge remote-tracking branch 'upstream/master' into norm_fix

Conflicts:
	sunpy/map/mapbase.py
Merge pull request #605 from wafels/wcs

WCS pull request to master
Merge pull request #596 from Cadair/norm_fix

Changed the norm() method of GenericMap to an attribute.
fixed conflicts in mapbase.py