BuildSystem: general, configure and Xcode updates.

BuildSystem: general, configure and Xcode updates.

*** NOTICE:
This changeset requires a clean build directory. Please issue 'make xclean' inside
build dir(s) after 'svn up'. This will help ensure there are no unexpected results.

*** GENERAL:
- renamed makevar PROJECT/ -> SRC/ for clarity.
- renamed makevar PREFIX.install/ -> PREFIX/ for clarity.
- split custom GNUmakefile overrides into defs/rules files.
- inserted optional level of make customization at SRC/ level; see docs.
- dropped HB.repo.wcversion (svnversion is no longer used).
- corrected several 'rm' usages to use -f flag which avoids some build errors.
- refreshed generated 00-Building.*.txt docs; work still in progress on the wiki front.

*** CONFIGURE:
- made configure more robust; configure may now be run outside of build directory!
- adding log recording of configure activities.
- improved readability of default options for configure
- added:

    --force             overwrite existing build config
    --src=DIR           specify top-level source dir [.]
    --build=DIR         specify build scratch/output dir [.]
    --prefix=DIR        specify install dir for products [/Applications]

- dropped --launch-force (replaced by --force)
- dropped --launch-dir (replaced by --build)
- dropped --launch-log

*** XCODE:
- renamed pbxproj definition EXTERNAL_PROJECT -> EXTERNAL_SRC for clarity.
- fixed all configurations to default to EXTERNAL_JOBS=1 .
- enabled Xcode internal parallelization (libhb, HandBrakeCLI and HandBrake benefit).
- make now tickles Xcode build files to cause Info.plist regeneration and posting to HandBrake.app output;
  ie: svn up; click build and HandBrake.app's about panel will reflect the new repository rev.

*** DARWIN:
- added support to build universal binaries; see docs.

git-svn-id: svn://localhost/HandBrake/trunk@2242 b64f7644-9d1e-0410-96f1-a4d463321fa5