FULLPIPE: Fix cheat codes. Bug in original?
GRAPHICS: Implement JPEGDecoder based on libjpeg.
GRAPHICS: Make JPEGDecoder request RGB output from libjpeg by default.

This fixes loading of JPEG files which contain RGB color space instead of YUV.
It is a pretty odd extension of JPEG files by Adobe which is indicated by this:
http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe

To still support Groovie's need for YUV data I added some possibility to
request direct YUV output.
GRAPHICS: Add some paranoia asserts in JPEGDecoder.
SCI: QfG1VGA: script patch to fix a typo in a Sierra script -> looking at a cheetaur returned the text for saurus rex, fixes bug #3604943
Merge pull request #376 from lordhoto/libjpeg

GRAPHICS: Implement JPEGDecoder based on libjpeg.
BUILD: Disable Full Pipe engine by default.

The engine is still WIP and should not be enabled yet.
BASE: Add feature string for libjpeg support.
BASE: Add feature string for libpng support.
NEVERHOOD: Split the code that stops all music and sound effects
NEVERHOOD: Implement the music toggle menu button
DEVTOOLS: Adapt create_project for libjpeg support.

The library name of the static library is based on what libjpeg-turbo uses
which should be fine for Windows at least.

Untested except for compilation of create_project.
BUILD: Fix Mac OS X static build with libjpeg
GROOVIE: Fix ROQ JPEG decoding
TSAGE: Fixes and renaming for R2R forest
TSAGE: Bugfixes and renaming for entering ARM hanger, and more for Spill Mountains
NEVERHOOD: Slight cleanup in Module2800::updateScene()
SCI: script patch for larry 2 - fixes no points granted when wearing parachute - was a sierra script bug - fixes bug #3614419
FULLPIPE: Implement CMovGraph_messageHandler()
CONFIGURE: Better default for static lib prefix on OSX

Instead of always assuming /sw (i.e. fink) it should now also pick up
the macports prefix or /usr/local depending on which one exists.
Of course this can still be overwritten with --with-staticlib-prefix