fixed the cmake build system with regards to environment variables: these aren't referenced directly with $ENV{VAR} anymore to be able to pass them into cmake via the -D switch
using UNICODE
suppressing cmake dev warnings about linking with Qt
enabled the build system to take paths to third party dependencies from environment variables or directly from a cmake variable (passed in via the -D switch to cmake)
Merge pull request #123 from augmented-go/build_system_changes

Build system changes