Fixed|Builder: Error when generating the XML feed

The OS X 10.6 packages are still present in the earliest 1.15 builds.
Fixed|Debian: Package build rules (linker path)

libassimp is built in a nonstandard location (under external).
Refactor: Renamed libdeng1 to liblegacy (deng_legacy)
Refactor: Renamed libdeng2 to libcore (deng_core)
libshell: Bumped version number to the project version

The development version 0.1.0 no longer applies.
qmake|Unix|libgui: libgui implies dependency on libassimp
Debian: Updated package build rules after recent changes
libcommon|GameSession: Removed use of busy mode for saving the game, cleanup

Using busy mode for saving the game is somewhat pointless given that
it usually takes longer to perform the busy mode setup than it does
to serialized the game state to a new .save package.
Merge branch 'master' of github.com:skyjake/Doomsday-Engine
libcommon: Cleanup

G_ApplyCurrentSessionMetadata() now defaults the SessionMetadata
user description to "(Unsaved)", for GameSession's convenience.
libcommon|GameSession: Always update rather than replace internal .save

For some reason FS2 is complaining that it cannot replace the Info
when performing an update even though the .save package is apparently
writable.
Fixed|libcommon|GameSession: Replacing internal .save Info

Following File::reinterpret() one must manually (re)populate()

IssueID #1791
Fixed|libgui: Warning about floating point conversion
Merge remote-tracking branch 'remotes/origin/master' into revise-map-geometry-generation