startup script updates.
add ginga_sunpy path to sys path in startup script.
Use astropy helpers for install.
Make a documentation build complete correctly.
Use ginga.main.global_plugins to add the plugin.
Startup the SunPy plugin earlier and remove random print statement.
Both ginga starts and sphinx builds!
Merge pull request #3 from Cadair/ah_sunpy_ginga

Ah sunpy ginga