Decode 2.8.1 Release Candidate 1

### Added
- Strava social link
- ResearchGate social link
- Deviant Art social link
- Slideshare social link
- Show featured images on entry excerpt option
- Russian Translation

### Improved
- Post navigation
- Updated translations
- Updated Modernizr and Respond.js

### Fixed
- Escaped image URLs to fix domain content security errors
- Fixed German translation error