Support for Mingw64 compiler

This patch set adds support for the compilation of Lunchbox with MinGW64.

The changes were tested with commit acb7920fbc151cf32e664325a442134af142332b as a branch base using MinGW64 runtime 3.2 on Linux. The library files were created without issues and the tests linked properly against the library.
define LB_USE_STD_PARALLEL