Assume that tutorial programs have already been run
Take output directory as command-line parameter

These changes make it easier to call the program from a generated
Makefile rule, since only the Makefile knows where the output tree
is (containing the rest of the documentation).
Put figure generation program with number generation programs

Since the data files are generated by the tutorials, it is natural to
have the figure generation program also together with this source code;
otherwise people may think that it have to be used for *all* figures
Explain how to rebase feature from CMake-test to master

Using this procedure, one can develop on the CMake branch (for instance
using QtCreator), but submit patches on the master branch.