scope filters implementations for translation

[knitzsche]

Hi,

Ubuntu Devices release OTA 10 supports filters [1] for scopes.

I would really appreciate some help getting the new filter text 
translated for a set of scopes that now have filters implementations.

Most have just a few new strings.

Screenshots of the new filters are here: 
http://people.canonical.com/~knitzsche/scope-translations/14april2016/

* Yelp: https://translations.launchpad.net/yelp-scope
* Calls: https://translations.launchpad.net/calls-scope
* Texts: https://translations.launchpad.net/texts-scope
* Facebook Photos: https://translations.launchpad.net/facebook-scope
* Holidays: https://translations.launchpad.net/holidays (lots of holiday 
types to filter on)
* 500px: NEWLY AVAILABLE SCOPE SOURCE: 
https://translations.launchpad.net/500px-scope

Also:
* dropbox photos scope had a couple small string changes (not relating 
to filters): https://translations.launchpad.net/dropbox-scope

Cheers - appreciate the great work!
Kyle

[1] Filters enable users to refine results displayed in various ways.