Changed "colors" app nam in enabled apps config to "showcolors".

Fixed gitinfo application, now it would not spam on jist-git-init'ed
repos, fixing #1.
Also reworked checks things, now every function will call
gitinfo_internal_checks function and do nothing if internal checks
method returns 1.

zsh/defaults/02-apps.conf

@@ -1,2 +1,2 @@
 # Apps list to enable.
-ENABLED_APPS=("colors")
+ENABLED_APPS=("showcolors")