CMake build system for cfl3d

[ghost]

In order to make build system more robust and parallel. I replaced it with CMake build system. And I just merged it with the newest nasa/cfl3d. I just checked the comparison of files modified:

• build directory is purged, all makefile_cpp and makefile, Install, makefile_xx_examples are removed.
• add a build/bin/create_use_cfl3d to add alias use_cfl3d="export PATH='\$HOME/cfl3d/CFL3D/build/bin:\$PATH'"
• cputim.F is modified to be compatible with gcc/gfortran
• spalart.F is modified to solve complex version problem.
• a lot of CMakeLists.txt are added to create the cmake build system..

Now you only need

cd CFL3D/build
cmake ..
make -j`nproc`

That's all.

[crumsey]

Cmake build system is a great idea, but currently we want to keep the original way as well. So it would be nice to have it as an optional addition, without removal of the old style. Also, best if commits are kept simpler (not so many changes in the same commit)... makes it much easier to adopt them wholesale. We do not want to include CGNS library here, nor files from the TMR website... those are kept independently. Thanks for finding the minor issues; many have been implemented independently.

[weijianwen]

This PR seems duplicate with #4 with some irrelevant chages regarding to adopting CMake. I recommend to keep things as they are if they are not obstacles for CMake. Better one commit for doing one thing.