buildscripts: add mumble-win32-dll.bat, a script that does an official Mumble 1.2.x build.
buildscripts/mumble-win32-dll.bat: add plugin replacement and internal signing steps.
buildscripts/mumble-win32-dll.bat: add explicit MumbleZlibDir to fix 1.2.x build.
Add LICENSE, LICENSE.header, AUTHORS and CONTRIBUTORS files.
buildscripts/mumble-win32-dll.bat: add license header.
buildenv: update build-qt4.bash for all platforms to be in sync with mumble-developers-qt HEAD.
buildenv: use '/bin/bash -ex' instead of '/bin/bash' for all buildenv scripts.
buildenv/win32-static: add cygwin install dir querying to cygwin.cmd.
buildenv: duplicate build envs into separate 1.2.x and 1.3.x variants.
buildenv: update 'osx' build environment to use same build-script style as 'win32-static'.

Also add a real 'setup' script, like 'win32-static'.
.gitignore: add initial gitignore.

For now, just ignore .DS_Store.
buildenv: fix setup.command for OS X to be whitespace aware.
buildenv: more whitespace fixes for OS X's setup.command.
buildenv: fix OS X's setup.command to not use $MUMBLE_PREFIX.

Also fix some stdout and stderr redirecting for some of the
script's external commands.
buildenv/1.3.x: remove osx-universal build env.

1.3.x is going to use Qt 5, which is is Cocoa/10.6+/Intel only.
buildenv: update 1.2.x/osx-universal to use same build-script style as 1.2.x/osx.
buildenv/1.2.x/osx-universal: fix build-all.bash's reference to build-libtool.bash.
buildenv/1.2.x/osx-universal: re-add accidentally removed -Wl,-search_paths_first from build-libxar.bash.
buildenv/1.2.x/centos-ermine: fix up centos-ermine build env to match the osx/osx-universal/win32-static style.
buildenv/1.2.x/centos-ermine: ensure that MUMBLE_PREFIX_BUILD is exported in 'env'.