Complete compton-trans manpage

[evamvid]

There are several options/flags in the compton-trans source that aren't listed in the manpage (the -g, -r, and -d flags). It's also not specified if the -o flag is necessary, or if opacity is only supplied as a positional argument.

I can fix this myself, if someone can help me with the manpage synopsis format. I'm having trouble specifying that you don't use (for example) -g with any either -s or -o, (i.e. you can't get and set at the same time).