Use relative path if the Cantera install directory contains spaces, as the
Makefile 'include' statement doesn't seem to have a way to escape the space
otherwise.
For some compilers (gfortran), there is no space in the argument for specifying
a module directory, e.g. '-Jdir', while for others (ifort), there is,
e.g. '-module dir'. This substitutes the correct prefix directly into the
compiler command line to avoid the confusion associated with having a variable
defined with a meaningful trailing space.
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.
