fix header
basic model implementation
let wormhole_endpoints know their galaxies
add planet factory
introduce common base class for planet attribs
add starsystem factory
add destructors
enable c++11
add sourcefiles to cmake config
enable random enum attribs
Fix linker errors
add initial gui stuff
fix (almost) the win32 build
fix build for windows :)
enhance platform handling on windows

enforce previous sourcing of MSVS vcvarsall.bat, set target platform based
on chosen vsvars*.bat
refactor cmake files

handle global platform-specifics in separate modules
play around with SDL library