Ubuntu Medium as a working font pair in Ubuntu 12.04

Ensure the ability to fully use Ubuntu Medium in Ubuntu 12.04

This is needed for the typographic review of the user interface. It will be necessary to be able to ship and use Ubuntu Medium and Ubuntu Medium Italic without advise effects on the rest of the interface.

Currently a metadata loss occurs in FontConfig, the font matching framework used on Linux. Data that is (incorrectly) presumed to be duplicated is discarded, later causing the substitution of Ubuntu Medium with Ubuntu Bold or vice-versa at higher up levels of the stack in Qt and Gtk+. Similar issues occur with the Linux Libertine typeface, another advanced font with multiple weights within the same family.

To implement, this will require upstream fixing of FontConfig and associated libraries to fix the model. To encourage completion or this, Ubuntu Medium will be once again re-uploaded to the 12.04 archives at an early stage.

  LP bug #744812. There's a data-loss (discarding additional meta-data on the assumption that it's duplication, when it's not) in FontConfig, which is perpetuated by anything that follows FC's data-model and presumptions (Qt, Gtk+).

  I keep not getting far enough stuck to work out a decent solution. But two guesses at the moment are either to duplicate entries (give two slightly different entries) within the current model, or to extend the data-model to cope with the meta-data in the fonts themselves.

  I believe that other OSs have two basic API entries; a "dumb" mode that just matches on string:name + bool:bold + bool:italic, and an advanced selection mode that selects based on string:name + integer:weight + integer:slant + string:style + etc.

  The two advanced open fonts it affects are Ubuntu (shows up particular with Medium) and with Linux Libertine.