Refactor: Added libgui, separated TextApp and GuiApp

libgui extends libdeng2 with GUI-related code. libdeng2 itself no longer
depends on QtGui, only QtCore and QtNetwork.
Client|Server: Dropped GUI/input dependencies in server binary

The server has no input devices, and therefore needs no bindings either.
Both the input and bindings subsystems were dropped from the server.

The text-mode console was dropped altogether from both client and
server builds (to be replaced with the Shell).

The window manager was dropped from the server, which is now a TextApp.
Server: Must not depend on OpenGL
Windows|Server: Removing OpenGL dependencies
Server: Cleanup
Refactor|Client|Server: Split dd_init to main_server and main_client

Both applications now have their own main() functions.
libshell: Relocated LogWidget and CommandLineWidget to libshell

These two widgets are generic enough to work in a GUI Shell as well.
Shell: Started setting up the GUI Shell app

QtGui-based App class, Mac OS X deployment.
Shell: Text canvas rendering on Qt bitmaps
libdeng2: Utility for the pimpl idiom

The DENG2_PIMPL macro makes it somewhat easier to define a private
implementation struct that contains a reference to the public instance.
Shell: Apply the DENG2_PIMPL macro
Shell|Qt: Improved QtRootWidget, added command line and log widgets
Shell: Implemented character attribute for blinking

Separately from cursor blinking.
libshell|LocalServer: Allow specifying additional options
libshell|Fixed: Set the random seed number for ServerFinder
Shell|GUI: Setting up the menus, added ServerFinder

The local servers appear in the menu.
Server|Fixed: Bias surfaces are meaningless, should be ignored

The server was crashing when trying to move a plane (e.g., open a door)
because it was trying to access unallocated arrays.
Refactor|Fixed: Server planes array now uses a QList

Replaced the C-style dynamic array management with a more robust
QList. Fixes a crash at shutdown in MP games.
Server|Debug: Investigating initial player mobj angle
Server|Fixed: Initial player mobj angle

The player think functions that deal with player controls must be
skipped altogether on the server. They were causing the player mobj
angle to be set incorrectly.