Allow specifying the include path for FMILibrary.

On Windows the FMILibrary include directory is not always available
under PATH OR /usr/include. So use cmake -DINCLUDE_PATHS=<path to
include directory> to specify the location.
Fixed the build for Windows

+ Allow specifying the FMILibrary path.
+ Real time mode is not available for Windows.
+ Added a Windows implementation for realpath.
Don't use unix style temp path. Let FMIL find the temp path. Check for the FMI 1.0 fmu type.
Always write the result file.
Added LINK_DIRECTORIES usage in README.