These changes make it unnecessary to copy header files around during
the build process, which tends to confuse IDEs and debuggers. The
headers which comprise Cantera's external C++ interface are now in
the 'include' directory.
All of the samples and demos are now in the 'samples' subdirectory.
This changes removes a nonstandard include cpp implementation that
was the cause of the error.
Now the CVode or sundials choice is implemented within the makefile.
