- Add C11_COMPILE cmake option that creates a static lib instead of header-only
- Add C11_INLINE macro that depends on C11_COMPILE
- Split App.hpp into App.hpp and impl/App_inl.hpp
- Add App.cpp that compiles App_inl.hpp into an object file
- CMake modifications to handle impl headers differently for sinlge-header, headers-only, and compiled versions
