fixed ticks_labels_grid
added remote-data decorator to BaseImageTests class
Merge pull request #65 from anizami/fix-docs

fixed ticks_labels_grid
moved remote-data decorator
fixed errors
Make sure reset_wcs doesn’t need to change frame_class (should only be set once, during __init__)
uses header files instead of the hdu object
cleanup
Merge pull request #67 from anizami/remote_data-decorator

added remote-data decorator to BaseImageTests class