* add default visibility to most APIs in program_state
* remove unwanted C++ headers
* Add symbol visibility pragmas and compiler flags
* Add visibility attribute to APIs in channel_descriptor and hip_hcc
* remove unused headers
* simplify build flags with hcc
* add pragma visibility hidden to functional_grid_launch
* [CMake] add gfx908 back
1. hipHccModuleLaunchKernel is same as hipModuleLaunchKernel with OpenCL workitem model
2. Added copy right
3. Fixed header naming
Change-Id: I6a7c35a3566e2f8d3f5056613e34193775d4b236
Siu Chi Chan
Maneesh Gupta
Laurent Morichetti
Aditya Atluri
pensun