Added some comments to the DataFile module to make the inheritance make some more sense. Also restructured the way get_data is implemented so that there was a more logical lineage to the base HDF5 class. Could possibly still use some work, but it should be okay for now. Caught some exception stuff for plotting spectra so that there arent yucky errors every time you try to plot one with a file that has no energy information.
added scalar output for the set plot function. Outputs value to a label in the control pane