#41 support target-dir for octave dynamic-link libraries/.m scripts

[Andreas Metzler]

Hello,

pfstools 1.x supported fine-tuning of octave installation directories (--with-octave-m-dir/--with-octave-oct-dir), attached patch inspred by Fedory restores this capability for pfstools 2.x (-DOCTAVE_OCT_DIR/-DOCTAVE_M_DIR)

cu Andreas