Loads of JS optimizations, minor tweaks here and there

* added JSHint, for consistent JavaScript Code Style and syntax check
* refactored the PhpBb data import process JS part with Flight Components
* added some vars accessible from Plugins hooks, like "$myPluginPath", "$myComponentsUrl", ...
* some HTML hooks are now prefixed with "component.". Guess what it is used for?
* added site title in HTML document head and page header
* added progress bars customization in our Twitter Bootstrap test theme
* some bugfixes & optimizations here and there
* replaced all the single quotes in JS files with double quotes