Various Bugs

[NathanJPlummer]

I found a few bugs. Most likely from the original code I added.

The following code did not work and instead gave my Guetlzing instructions:

guetzling -q 90 -k

However, if I specified Guetzling to only compress PNGs it worked:

guetzling -q 90 -p -k

However, it worked with this message:

QUALITY_JPG = 90
Recompressing PNG ONLY
Guetzling file at level '95' ...

It informs me I'm compressing at both 90 and 95.

I'll try to look into this later tonight.

[NathanJPlummer]

Add another bug, definitely new, more severe:

Guetzling definitely did not keep my PNGs.

[lejacobroy]

Thanks! I'll try to look into that before next week!
In the meantime, if you fix the bugs feel free to do a pull request!