i18n 6.x-1.4

Security update:
- Fixed multiple XSS issues with string and blocktranslations
Other bug fixes:
- Added some unit tests for strings, blocks and taxonomy
- Fixed: Block translations deleted on refresh, #732680
- Fixed: warning in node form causes PHP notice, by swentel, #664944
- Fixed: i18nblocks conflicts with modules and themes, by JohnAlbin, #457512
- Some clean up to i18nstrings API: Dropped update option from i18nstrings_translate()
- Disable content selection during synchronization, by Pisco, #648348
- Add CSS class to body tag based on language, by Garrett Albright, #661448
- Added compatibility with ctools page manager, by Kars-T, #698942
- Added support for taxonomy_override_selector, by hefox, #619726
- Fixed: Configure string translation tab not showing up, #732368
- Fixed: Views content negotiation filter not working, by markus_petrux, #650552
- PHP 5.3 compatibiliby issue, by Berdir, #623138