Fix of SVM class to inherit from Model and Block

This fix will solve the SVM class errors, but it won't give you a fully functional model, since channel list is empty. The model will train, but it won't give any interesting information on performance.

Example output:

    ....
    compiling begin_record_entry...
    compiling begin_record_entry done. Time elapsed: 0.007125 seconds
    Monitored channels: 
    Compiling accum...
    Compiling accum done. Time elapsed: 0.000096 seconds
    Monitoring step:
            Epochs seen: 0
            Batches seen: 0
	    Examples seen: 0



I think that should be `from pylearn2.models.model`, as we are trying to get rid of relative imports.