Allow to cross compile for Windows with Linux/Mingw (part 2 of 3, bugfixes) (#1149)
* #mingw #bug: place explicit instantiations on templates before first use
* #mingw #bug: remove API attributes from inline functions
* #mingw #bug: add 'static' attribute for local functions
* #mingw #bug: fix API attributes for splitSpeedInOutSegment
* #mingw #bug: replace strstream to stringstream
* #mingw #bug: remove cross references to plasticskeleton from tnzcore
* #mingw #bug: fix bug with order of initializaition of static variables
* #mingw #bug: fix glutInit