libcore|Xcode: Fixed a bunch of benign integer conversion warnings
OS X|Xcode|qmake: Script for generating an Xcode workspace

The Qt 5.3 qmake is incredibly broken when it comes to generating
Xcode projects, but this commit adds a script that cobbles together a
fully functional workspace that contains all the individual
projects that qmake generates.

xcode_workspace.py generates a workspace called "Doomsday.xcworkspace"
to the current folder.
Fixed|InFine: Compiler warnings (un/signed comparison; string literals)
Fixed|XG: Player armor set to limit when triggering XG 'power' class lines

Due to refactoring oversight back in 2009, the logic of the XG power
line class was changed to the effect that the player's armor value
would be set to the min/max limit if the amount of armor to give/take
was above/below that which the player currently has.

IssueID #906
Fixed|XG: Surface tint color changed when triggering XG 'plane_material' lines

Due to a refactoring oversight back in 2007, the logic of the XG
plane_material line class was changed to always change the surface
tint color when triggered (default is black).

Evidently, however, back when this was implemented originally the
necessary "Change Color" flag was omitted, so this was added also.

IssueID #965
libcore|FS: Added methods for iterating all found files

Supports lambda functions.
Unix|Client: Let de::App determine the base path
Resources|Manifest: Also use FS2 to locate files

While FS1 is still used primarily like before, this now allows looking
up the file anywhere in FS2, too. With this change, it is now possible
to launch Doomsday.app on OS X without any arguments (assuming the
IWAD folder is determined via other means) and things will just work:
the needed resources are located within the bundled game plugins.
Fixed|Windows: Bunch of benign warnings in the release build
Fixed|Client|Manifest: Added missing header
libcore: Better generic "for" pattern for C++11 style iterator methods
Oculus Rift|Windows|qmake: ATL no longer needed with LibOVR 0.4.2
Resources: Load packages specified with the -pkg option

The "-pkg" option specifies one or more packages to load at startup
and keep loaded indefinitely, regardless of loaded/unloaded games or
engine resets. The arguments are package identifiers, not file paths.

The behavior is similar to adding hardcoded load-at-init packages.

In the future, per-session packages are configured via the home screen
GUI.
Cleanup
Refactor|App|Client: More convenient method for accessing a Config variable
UI|Updater: Use alternate accent color for annotation labels
Renderer|LensFX: Added a resizing filter (pixel density)

fx::Resize changes the size of the frame buffer to produce a pixelated
appearance, either for performance or aesthetic reasons.

The variables "Config.render.pixelDensity" and
"Config.render.fx.resize.factor" control the amount of resizing. The
former applies globally, however is only shown in Video Settings when
using a HiDPI display mode. The latter is accessible via the Renderer
Appearance editor.

The global pixel density setting replaces video mode resolution
config on OS X (changing the desktop video mode is not supported on
OS X).
OS X|Client: Always show pixel density in Video Settings
Documentation|libcore: Elaborated on TaskPool's "done" status
Fixed|libcore|Animation: Updating current time

Before these changes, the current time being just a reference, it
may have gotten changed from another thread during the evaluation
of an animation's value. This would sometimes end badly.

Now the animation time is stored in a copy, so it will only get updated
when requested.