Aligned parameter naming.
No need to do extra splitting.
Nit: whitespace fix.
Allow passing an arbitrary user to user-* filters.

If no user has been specified the current user will be used. The feature
still needs to be exposed in the filtering UI.
Added user-specific filtering options.

These filters extend the existing ones in the filtering drop-down and are only
available when a username has been specified in the URL parameters.

Part of bug 2531.
Added optional `user` parameter for building translate URLs.
Moved queries to their own functions.
Linked numbers to actual units.

Pending: actual linking for accepted/rejected suggestions.

Part of bug 2531.