Fix templatefields, listings, empty repeaters and isset checks

This includes the following fixes:

#127: Translated Templatefields
#131: Add isset() check for $values['_locale']
#132: Fix formatting of @nealmarques 's PR
#137: Fix listings
#138: Do not try to save when repeaters are empty

And adds the flag_icon function to the readme to fix #116

Thanks to @nestordedios @nealmarques @panda-madness and @lenvanessen !