Added a new splash screen and made Code::Blocks Git aware

|BUILD CONFIGURATION|
[update_revision.sh]
* The Git version's major.minor.revision.build number as well as the tag used
  are incorpoated into a new m4 definition, GIT_REVISION_FULL
[configure.ac]
* Instances of GIT_REV are replaced with the GIT_REVISION_FULL from the
  update_revision.sh script

|SOURCE|
[src/include/autorevision.h.in]
* Using the GIT_REV instead of SVN_REV definition for the svnRevision string
[src/src/app.cpp | src/src/dlgabout.cpp]
* The new splash screen replaces the most current official release version
[src/src/appglobals.h]
* RELEASE is defined as "Git" instead of "svn"
[src/src/splashscreen.cpp]
* The text colour for the revision information has been changed to white so
  it's clearer than the black to see
* The X and Y position have been changed to better situate the text location
  against the new backdrop

|RESOURCES|
[images/splash_saturn.[png|xcf]]
* The SEGA Saturn Software Development Kit Integrated Development Environment
  splash screen
Added a script to create an installer using the Qt Installer Framework