Fix: don't include xaudio2 if you are not going to compile it

This is more in trend with other files, where if the driver is not
selected, we don't even attempt to compile it.

Remove: libtimidity support (NOT timidity support)

libtimidity was introduced with the support for PSP. PSP has been
dropped almost a year ago, but this music driver was not. This
corrects that oversight.

timidity (via extmidi) still works fine. This purely removes the
libtimidity support, which was only really available for PSP.

Remove: BeOS support (deprecated by Haiku)

In 10 years there is no commit to change how BeOS works, and we
have no active maintainer for it. It is unlikely it works in its
current state (but not impossible).

With the arrival of SDL2 (and removal of SDL), BeOS is no longer
support. SDL2 suggests to use Haiku instead of BeOS.

Change: Always build baseset metadata, instead of including it in the repo.

This adds a script and project files to generate these files within MSVC.

(svn r10190) -Codechange: merged renderer and blitter to one single class API: blitter
-Codechange: introduced a hierachy of blitters to avoid a lot of code duplication
Note: this allows much easier adding other types of video-drivers, like OpenGL

(svn r8832) -Change: rewrite the solution file generator a little so it makes project files that look more like the ones generated by respectively MSVC2003 and MSVC2005.
For some reason the internal formatting of the XML between MSVC2003 and MSVC2005 differs, so adding a file in MSVC2005 would result in basically adding the entire openttd_vs80.vcproj to the diff.

(svn r8326) -Fix r8304: forgot to update projects/generate to keep in mind the new WINCE tag in sources.list
-Fix: MSVC doesn't order files itself, so put win32.cpp in the right place ourself
-Update: update the MSVC projects files for r8324 (MiHaMiX)

(svn r7759) -Merge: makefile rewrite. This merge features:
- A proper ./configure, so everything needs to be configured only once, not for every make.
- Usage of makedepend when available. This greatly reduces the time needed for generating the dependencies.
- A generator for all project files. There is a single file with sources, which is used to generate Makefiles and the project files for MSVC.
- Proper support for OSX universal binaries.
- Object files for non-MSVC compiles are also placed in separate directories, making is faster to switch between debug and release compiles and it does not touch the directory with the source files.
- Functionality to make a bundle of all needed files for for example a nightly or distribution of a binary with all needed GRFs and language files.

Note: as this merge moves almost all files, it is recommended to make a backup of your working copy before updating your working copy.