Add deadline to lightbeam

At least temporarily, to see if we can manage to fix the missing
locales (en-US is currently waiting).
Add firefox/os/devices
Revert "Add firefox/os/devices"

This reverts commit 498145102e5c25faf6ff8ebd0249a7a0c1dc0898.
Add firefox/os/devices, without removing anything
NIT: array indent
Adding es-MX to os/index + os/devices
Adding es-MX for os/faq

(adding as well since the file is already translated)
Add Tamil (ta) to Pootle locales
add addons repo for worldcup (and future similar projects)
Add snippets for June (jun2014.lang)
Update deadlines
lang_update: stop on single file and unsupported locale

* Stop is we’re updating a single file, and locale is not supported.
* Add initial comment with possible usages
Merge pull request #129 from flodolo/issue29

lang_update: stop on single file and unsupported locale
contribute.lang: set to critical, remove double 'hr'
Add nl to June snippets