Move checks for graphics_toolkit GUI functions to own script. * __get_funcname__.m: New function to buid the function name from basename and graphics_toolkit. * uigetdir.m, uigetfile.m, uiputfile.m: Adapt to use __get_funcname__ with basename = mfilename ()

#include "mex.h"

void
mexFunction (int nlhs, mxArray *plhs[],
             int nrhs, const mxArray *prhs[])
{
  mexPrintf ("Hello, World!\n");

  mexPrintf ("I have %d inputs and %d outputs\n", nrhs, nlhs);
}