All changes from WIP 1 --> WIP 2

Misc:
- Normalize all file modes to 0644
- Removed extraneously included headers (this produces an 8% build speed-up on my system)
- Removed support for Windows OSes earlier than Windows XP (necessary to build against newer SDK; I don't think this is a problem nowadays)
- Added Visual Studio 2010 build files (and added their artefacts to .gitignore)
- Deprecated the DirectShow MovieTexture; will likely remove it in an upcoming release

Build process changes (Windows, VS2k10):
- Added a script to generate a Git info header identical to the Linux version (verinfo.h)
- Removed "Arcade" builds, changed home releases to "Release" and "Release-SSE2".

Build file changes (Linux):
- Add hack to build on aclocal 1.7/1.8 with incompatible argument
- Add hack to pull today's date for $build_rev_date if Git can't provide the revision date
- Removed -DLTM_DESC and -DLTM_SOURCE from libtomcrypt's Makefile (and defined them in tomcrypt_custom.h)

Libtomcrypt/libtommath changes:
- Added macros to tomcrypt_custom.h so we only pull in code we're using
- Fixed inclusion errors with tab files and added some missing conditional inclusions
- Added SSE2 release versions