which can be defined to call C functions with defined parameters. * Parameters are RNA properties, with the same types. * Parameters are stored in a ParameterList, which is like a small stack with the values. This is then used to call the C function. * Includes Python integration. * Only one test function is part of this commit, ID.rename. * Integration with the editors/ module is not included in this commit, there's some issues to be worked out for that still.