Add option to disable status notification

For certain git repositories, this slows down usage
of the shell horifically.

This option can be set with

    git config --add oh-my-zsh.hide-status 1

which will disable checking/showing the status notification

lib/git.zsh

@@ -8,13 +8,15 @@ function git_prompt_info() {
 # Checks if working tree is dirty
 parse_git_dirty() {
   local SUBMODULE_SYNTAX=''
-  if [[ $POST_1_7_2_GIT -gt 0 ]]; then
-        SUBMODULE_SYNTAX="--ignore-submodules=dirty"
-  fi
-  if [[ -n $(git status -s ${SUBMODULE_SYNTAX}  2> /dev/null) ]]; then
-    echo "$ZSH_THEME_GIT_PROMPT_DIRTY"
-  else
-    echo "$ZSH_THEME_GIT_PROMPT_CLEAN"
+  if [[ "$(git config --get oh-my-zsh.hide-status)" != "1" ]]; then
+    if [[ $POST_1_7_2_GIT -gt 0 ]]; then
+          SUBMODULE_SYNTAX="--ignore-submodules=dirty"
+    fi
+    if [[ -n $(git status -s ${SUBMODULE_SYNTAX}  2> /dev/null) ]]; then
+      echo "$ZSH_THEME_GIT_PROMPT_DIRTY"
+    else
+      echo "$ZSH_THEME_GIT_PROMPT_CLEAN"
+    fi
   fi
 }