Use "Gcc" instead of "Gpp" everywhere that we mean "GCC"
Update release notes for plugin rename
Added support for defining multiple CSourceSets for a native component

- Register the correct factory for CSourceSet
- Use the language source set name in the conventional directory path
- integration test
Added support for defining multiple C++ and Assembler source sets

- Register the correct factory for CppSourceSet and AssemblerSourceSet
- Use the language source set name in the conventional directory path
- integration tests
Fixed integration test