Added Quentities to the VSO wavelength properties

that includes:
Added a way to find which of the 3 possible inputs belongs the one being requested so we convert to the units VSO accepts
Added error catching to VSO wave and improved the way it catches the spectral units inputs. Also couple of tests added
Modify vso wave atributes to convert frequencies to kHz for VSO before doing the query
changed the way we compare the error messages so it works for py2.6
python 2.6 needs explicitaly said the order when using "{}".format()
Changed test to units supported for an older version of astropy (0.32)
updated hek to use and parse quantities in Wave as VSO - The wave_unit_catcher() is not needed anymore
Propagate the changes of quantifying VSO wave to database and its tests