Updated .gitignore
Add top-level grid() alias
Fix bug with WCSAxes.grid, since it gets called before ``coords`` gets initialized, with ``draw_grid=False``
	modified:   wcsaxes/__init__.py
	modified:   wcsaxes/axislabels.py
	modified:   wcsaxes/coordinate_helpers.py
	modified:   wcsaxes/coordinate_range.py
	modified:   wcsaxes/coordinates_map.py
	modified:   wcsaxes/formatter_locator.py
	modified:   wcsaxes/frame.py
	modified:   wcsaxes/grid_paths.py
	modified:   wcsaxes/slice.py
	modified:   wcsaxes/ticklabels.py
	modified:   wcsaxes/ticks.py
	modified:   wcsaxes/transforms.py
	modified:   wcsaxes/utils.py
	modified:   wcsaxes/wcsaxes.py