Merge pull request #13 from uploadcare/multiupload

Multiple file upload
Require all added translations
Default locale fallback
Localized templates
Moved l10n from locale/locale to locale
Pass current lang to social iframes
Pluralizable messages
Locale overrides
Shorter file button title
Latvian locale
Rails-like pluralization nouns

Rules rewritten from:
http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html
Comment on pluralization rules
Crop widget

WIP
Fix jCrop style (add image)
Fix crop widget usage example
Crop widget refactoring
Use pluralization for current locale only
Merge pull request #14 from uploadcare/i18n

I18n
typo
Accept all falsy values as "not set" for size options in crop widget