CommonUri added.

Contains two functions: getFilename + getUrl.
CommonUri: @param comment updated
Changelog improvement added
CommonUri: decoding htmlspecialchars
CommonUri: remove special characters by their normal character
CommonUri: return added
CommonUri: reserved characters (RFC 3986) comment updated
CommonUri: '|' needs to be replaced
CommonUri: removed redundant space, etc...
SpoonFilter::urlise replaced by CommonUri::getUrl
CommonUri: RFC comment changed
CommonUri: additional cleanup added
self not found, needed to be SpoonFilter
Nicer event tracking in Google Analytics
Add category questions to front-end page

Add only the questions of a category to a front-end page using the
widget selector
Fixed padding so it respects the code style guidelines
Fork Standards applied
Removed trailing spaces
Added Greek language + Other language updates
Added translations updates to changelog