Without these functions, it was impossible to use these classes
without leaking memory. Even with these functions, the memory is
released only when these functions are explicitly called, as
old-style Matlab classes have no notion of a destructor.
Fixes#252.
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.
