Make coord_type_from_ctype return a default coord_wrap
Add coord_type_from_ctype tests.
Merge pull request #19 from Cadair/coord_wrap

Make coord_type_from_ctype return a default coord_wrap
spacing has to be quantity for ScalarFormatterLocator
added format_unit to change units
oops forgot to remove a * self._format_unit
added set_format_unit method
AngleFormatterLocator now takes quantities, updated CoordinateHelper accordingly
specifying units works now,merged conflict
fixed some variables change errors
cleaned up some code
removed some more spaces
small change to locator method