PATH = VL_SETUP() adds the VLFeat Toolbox to MATLAB path and returns the path PATH to the VLFeat package.
VL_SETUP('NOPREFIX') adds aliases to each function that do not contain the VL_ prefix. For example, with this option it is possible to use SIFT() instead of VL_SIFT().
VL_SETUP('TEST') or VL_SETUP('XTEST') adds VLFeat unit test function suite. See also VL_TEST().
VL_SETUP('QUIET') does not print the greeting message.