Fixed extra paren in GAudioOutput.cc
Broke windows compilation.
Added details for platform/build requirements.
Also added Qt version check.
And made the platform/toolchain check a little more descriptive.
Make sure we error on supported platforms.
Remove isnan() and isinf() templates from QGC.h for Windows builds

Remove isnan() and isinf() templates from QGC.h for Windows builds, this
generates errors (already defined in math.h).
Remove isnan() and isinf() templated from QGC.h only if prior to Visual Studio 2013
Describe which Qt variant to choose for a Windows build
Update QUpgrade
Remove non-needed files for MAVLink - we just want the C library
Remove drawing lib
Decode radio status and emit signal. Not used anywhere yet
Merge pull request #756 from Susurrus/build_fixes5

Some build improvements
Merge pull request #757 from Kynos/master

Remove isnan() and isinf() templates from QGC.h for Windows builds
Merge remote-tracking branch 'mavlink/master'