Use VS2012 as the default for the builds.

We've been using VS2012 for the nightlies for some time now without any real issues apart from the renderer one which was reported and worked around.
This will allow us to use more C++11 features.

No files are renamed or removed at this point; we'll do this after 1.7.0 is out.
build.bat: tabs to spaces.
Enable LTCG for VS2012 by default for Release builds.

The reason we disabled LTCG in the past was issue https://trac.mpc-hc.org/ticket/2508 which I cannot reproduce with VS2012 Lite LTCG x64 builds so we can assume this is fixed now.
coverity.bat: Use VS2012.
sign.bat: Use VS2012.
Clean-ups in the options.
Update LAV Filters to version 0.58.2-58-edab5dd.

Re-enable the "Resources" tab for MKV files with attachments using a custom patch for now.
version.sh: ditch SVN version numbers completely and use git describe

Side note: As a cosmetical change, if no git is present, the hash won't
be added to the full version string anymore as useless " (00000000)".
version.sh: refactor to improve messages when no git available or not a git repo
version.sh / mpc-hc.exe.manifest: generate full version number

Get rid of the redundant definition of the fixed version number
in mpc-hc.exe.manifest.conf.

Instead, use the values from config.h and write the whole version
to the manifest file.

version.sh is now the only place where version numbers need to
be changed.
version.sh: add two more echo commands to print some useful information

- echo MPC_VERSION_MAJOR.MPC_VERSION_MINOR.MPC_VERSION_PATCH
  gathered from version.h
- echo full git-describe output
version.h: Don't mention the revision in stable releases.

It will always be 0 in that case.
Rename Beta to Nightly.