Fixed issue #280 by using the locale and eventually a fallback to define the HTML to be in line with the application locale.
Merge pull request #319 from pvankouteren/issue-280-language-settings-locale-in-header

HTML lang attribute fix
Prevent slugs from ending with a '-'.
Don't show titles/names twice in contentrow. Fixes #312.
Finetuning the new 'add dummy content' functionality. Closes #241
Minor CSS tweak.
make sure we're not trying to access bolt as "/index.php/bolt/", because all paths will be broken. Fixes #277.
New feature: Config setting for favicon location. Fixes #276.
Fixed a missing translation.
Minor fixes in users.php.
changing package for Doctrine from '2.3.x' to '2.4.x@dev'. working on #320.
Fixed filling DB with Loripsum, when all content types are emtpy.
Fixed notice. Related to #277.
Prevent "Flash of unstyled content" for debug bar.