Update editor-style.css

- Bring in latest Bootstrap changes

- Add instructions on how to update the file
Update danish lang files
Update CHANGELOG with changes since 6.3.0
Comments clean up, consistent formatting
Update doc/usage.md

HTML5 Boilerplate documentation link was incorrect.  
Merge pull request #687 from ShutterBrandon/patch-1

Update doc/usage.md
Root relative URLs
comment
added conditional
Fix (hack) for subdir installs
Merge pull request #688 from damianregan/relativeurls

Relative URL fixes
Fix for admin bar
Merge pull request #691 from damianregan/relativeurls

Fix for admin bar
Update lib/h5bp-htaccess

Removed redundant duplication comment. Just a tiny a tiny thing
Merge pull request #694 from adam-lynch/patch-2

Update lib/h5bp-htaccess
updated russian translation
Merge pull request #695 from sumkincpp/master

Updated russian translation
Simplify wp_title()

We recommend you use the WordPress SEO plugin for <title> management
Ref #699 - Update to Bootstrap 2.3.1
Added Greek language translation