Feature: Wintype-specific options in configuration files

- Add support of window-type-specific options (fade, shadow, and
  opacity) in configuration file parsing. Syntax shown in
  compton.sample.conf.

- Replace wintype_name() with an array of window type names. Code
  clean-up.

compton.sample.conf

@@ -27,3 +27,9 @@ fade-out-step = 0.03
 
 # Other
 mark-wmwin-focused = true;
+
+# Window type settings
+wintypes:
+{
+  tooltip = { fade = true; shadow = false; opacity = 0.75; };
+}