Add guiding quality as a file name option

Another feature request I would really love - having guide quality as a file name option something like if you select %gq you get a value from great to bad returned based upon the worst guding during the imaging. So it could either return a numeric value - like the maximum correction for PHD (e.g. likely from 0.01 to 5.00) or it could use a descriptor based upon a maximum corrector range - such as:

Under 0.2 = Brilliant
Under 0.5 = Excellent
Under 0.7 = Great
Under 1.0 = Very Good
Under 1.5 = Reasonable
Under 2.0 = Workable
Under 3.0 = Bad
Over 3.0 = Terrible

Many thanks for your consideration,

Matthew