I have a fix to make in it and it's really silly to pretend that this
lib is of any use to anybody outside HS apps. Bringing it back here will
make things more simple.
Following the refactoring that has been initiated in pdfmasher's
"vala" branch, I pushed more progress window logic into the
core.
The UI code is now a bit dumber than it used to be, and the core
now directly decides when the progress window is shown and
hidden. The "job finished" notification is also directly sent by the
core. Job description update logic is handled by a core gui
textfield.
Job description contsants also moved to the core, triggering
a localisation migration from "ui" to "core".
