fixing spectrum.py to be compatible with Qt
fixing spectrum.py to be compatible with Qt

ContinuumIO/chaco,tommy-u/chaco,tommy-u/chaco,ContinuumIO/chaco,burnpanck/chaco,ContinuumIO/chaco,ContinuumIO/chaco,burnpanck/chaco,burnpanck/chaco,tommy-u/chaco