Changes to resolution modulus and scaling

I have added options to define the modulus used for determining valid resolutions. Now you can choose between mod2, mod4, mod6, mod8 or mod16. Before mod16 was enforced meaning you could not encode in many valid resolutions like 1080p. I have only specified mod2 for x264 and all other formats use the old mod16 since I am unsure what modulus those are compatible with.

Also I have added scaling options for if you would like to scale by width or height. This gives you greater control over the final resolution.