Sagenlicht, could you consider releasing it under LGPL? This way people can use it on commercial applications without having to release all of their codes, however if any improvement is made to the LPGL code then this portion of code must be released.
So your tool will always be free while having commercial applications also able to improve on it.
If possible then I could make a C++ DLL and a Qt/C++ DLL so more people will be able to use it.