Misc #152: Fix a spelling mistake

Fix a spelling mistake (xr_glx_hybird -> xr_glx_hybrid). Thanks to cju
for reporting.
Misc #163: Make usage of glFinish() optional

Make usage of glFinish() optional to avoid high CPU usage. (#163)
Merge branch 'richardgv-dev'
Merge branch 'master' of https://github.com/chjj/compton

Because git thinks I have to but it's wrong.
Window Color Inverter
+Improved help output for bad window ID