MSVC issue. SP_API can't be used on classes with methods inherited from templated classes like ConstraintGeneric::getData(). we need an intermediate class that gets the method instantiation, and derrive from that instead.
- spine-cpp/spine-cpp was moved into spine-cpp directory, so spine-cpp/spine-cpp/src -> spine-cpp/src, spine-cpp/spine-cpp/include -> spine-cpp/include
- Added scaffold for DebugPrinter to be used by runtime comparison tests
- Added build.sh