add header file to gyp
add header file to gyp

tangrams/earcut.hpp,mapbox/earcut.hpp,tangrams/earcut.hpp,mrgreywater/earcut.hpp,mrgreywater/earcut.hpp,mapbox/earcut.hpp,tangrams/earcut.hpp,tangrams/earcut.hpp,mrgreywater/earcut.hpp,mapbox/earcut.hpp