added a simple specwcs framework
added a linear wcs and an init file. now testing
added a simple from_fits method for reading the keywords from a simple linear fits wcs
unified the lookup table wcs class
fixing up the spectrum1d class to be specwcs compliant
fixed up spectrum1d to work with initial specwcs
added dispersion and flux units
added uncertainty column to from_table
small fixes
fixed the flux_unit and dispersion_unit
changed absolute imports to relative imports
Merge pull request #22 from wkerzendorf/specwcs

Spec WCS - first implementation
changed all the occurances of "disp" to "dispersion"
fixed some pep8 issues
fixed from_table documentation
added flags to the from_table classmethod
pep8 fix
Merge pull request #23 from wkerzendorf/refactor_dispersion

Refactor dispersion
added a check to see if uncertainty unit and flux unit match
several fixes suggested by the list