Refactor: Added libdoomsday, relocated some files

libdoomsday is the common denominator between the client and the
server applications.

Unlike liblegacy, it is intended to be a permanent and central part
of the architecture. All shared functionality that exists both in
the client and the server (but not at a more general level) should be
relocated there, after appropriate refactoring.

Relocated the following:
- logical sound manager
- old WAV parser
- base mobj struct declaration
- DualString
Git|Windows: Ignore generated .rc file
Cleanup
Refactor: Relocated console, FS1, and help to libdoomsday

This sizable commit relocates a couple of the most central Doomsday
subsystems into the libdoomsday library: console, FS1, and help.

Very little functionality has actually changed, though:

- Uri is now in libdoomsday, so it needs to use a callback to
  resolve symbols in the URI.

- FS1 depends on ResourceClass, however the resource subsystem is not
  ready for relocation; a callback was added to allow getting a
  ResourceClass instance based on its ID number.

The old console implementation has been cleaned up by splitting it
into several source files.

These changes enable relocating other subsystems that rely on console
and FS1.
Fixed|libappfw: Slider range labels shouldn't use scientific notation
Merge branch 'master' of ssh://github.com/skyjake/Doomsday-Engine
Fixed|Console: "clear" is a client-side command
Merge branch 'master' of ssh://Air-Force.local/~jaakko/Projects/deng
Refactor: Moved old WAV loader to libdoomsday and resource domain

This is analogous to, say, a PCX loader.
Windows|libdoomsday: Exported all public symbols

Also, the Windows version of strcasestr was moved to liblegacy (from winit),
so that it is available to FS1 in libdoomsday.
Fixed|Console|libdoomsday: Adding all games as known words

Added a callback for app-specific known words. libdoomsday has no
access to the set of all games at the moment.
Cleanup|Client: Removed UI background InFine script

The UI framework is in control of drawing the UI (background included)
so InFine is no longer being used for this purpose.

In the future, once there is Doomsday Script based InFine and an
InfineWidget, the window background image might be replaced with one,
though.

Fixes the warning where the background finale was trying to access the
removed "background" image resource.