Feature #75: Invert window color

- Add window color inversion (--invert-color-include). It means 2-3
  times extra painting, so performance issues are likely to appear.  I
  hope I could find a faster way to invert colors.

- Rename some functions.

- Fix update of some window properties after window type/data change.
  Hopefully this will be helpful for #73.

- Split win_build_picture() from win_blur_background().

- Correct memory leak of ps->focus_blacklist during reinitialization.

- Add win_upd_t and win_upd_run(), to reduce duplicate window property
  updates. But is unused right now.

- Limited tests are done overall. Bugs to be expected.

compton.sample.conf

@@ -48,6 +48,7 @@ unredir-if-possible = false;
 focus-exclude = [ ];
 detect-transient = true;
 detect-client-leader = true;
+invert-color-include = [ ];
 
 # Window type settings
 wintypes: