C++ API header file install

[DaniloNoguera]

Hello, in openfast/glue-codes/openfast-cpp/CMakeLists.txt there is a small error, the path src/SC.H must be changed to src/SC.h, as in previous versions to avoid error. Thanks for attention.

[rafmudaf]

Hi @DaniloNoguera this has been fixed in the dev branch via #768.