Add support for windowless applications on OS X.
Build fontconverter and distancefieldconverter on windowless OS X.
package: deleted MinGW32 PKGBUILD.

Replaced by MinGW-w64 in ArchLinux.
Enable command-line utilities on OSX.
Don't link unneeded libraries in commands.
Mention WindowlessCglApplication in FindMagnum.cmake.
Properly credit all contributors.
Platform: use delegating constructors.
Math: make the constructors in test also constexpr.
Math: no need to use class here.
package: added MinGW-w64 Jenkins CI configuration.

Also mentioned forgotten NaCl configuration in docs.
modules: updated FindCorrade.cmake.
modules: expose separate plugin directories for debug and release builds.
Be consistent and use our own platform definitions.
Merge commit 'df05a2d8a50993968557f6d00' into compatibility
Merge commit '098132f869e69cb' into compatibility

Ignored, as it breaks GCC 4.6 compatibility.
Merge branch 'master' into compatibility

Conflicts:
	src/Magnum/Math/Test/MatrixTest.cpp
	src/Magnum/Math/Test/RectangularMatrixTest.cpp
	src/Magnum/Math/Test/VectorTest.cpp