Escape % in $CMD variable

Fixes formatting on some rare cases when a percent ends up
in the $CMD variable, like these below:

- When assigning a variable, $CMD ends up with the second parameter;
in this case, $CMD will contain '+%s%N', messing with the syntax:

 $ a=`date +%s%N`

- A function (or command in general) that contains a percent symbol:

 $ to\%() { echo $(( $1 * 100 / $3))\% } # $CMD=to%()
 $ to% 2 of 10 # $CMD=to%

lib/termsupport.zsh

@@ -26,8 +26,11 @@ function omz_termsupport_precmd {
 function omz_termsupport_preexec {
   emulate -L zsh
   setopt extended_glob
-  local CMD=${1[(wr)^(*=*|sudo|ssh|rake|-*)]} #cmd name only, or if this is sudo or ssh, the next cmd
+
+  # cmd name only, or if this is sudo or ssh, the next cmd
+  local CMD=${1[(wr)^(*=*|sudo|ssh|rake|-*)]:gs/%/%%}
   local LINE="${2:gs/%/%%}"
+
   title '$CMD' '%100>...>$LINE%<<'
 }