- removed squirrel & sqrat sources, added sqapi as git submodule dependency
- removed module api (it's now included from sqapi target)
- removed unnecessary boilerplate from CMakeLists.txt
- Under linux pch.h won't work as expected, instead it will slow down build time. In order to fix this, target_precompile_headers cmake function must have every header that will be used in pch.hxx generation.
- Using the opportunity i've removed headers that aren't essential in precompiled header
- renamed sqmodule_api.h/.cpp to module_api
- moved defines for sq_* functions into squirrel_api.h
- renamed SqModule::inti to SQModule::Init
- moved all of the files to "api" subfolder