Allow compiling/installing generated Python files

Modify ctkMacroCompilePythonScript to accept SCRIPTS and/or RESOURCES
that are generated files, rather than requiring them to exist at
configure time. Also, modify ctkFunctionAddCompilePythonScriptTargets to
accept additional arguments that are passed to add_custom_target. (The
second change allows passing e.g. 'DEPENDS <other targets>', which is
required to make the targets depend on other targets which generate the
aforementioned generated files, so that copying of the files will
succeed.)
Merge pull request #477 from mwoehlke-kitware/allow-generated-python-files

Allow compiling/installing generated Python files