v1.0.6: Bug Fixes and Fortran Backend Improvements

• fixed a bug that caused vectorization to fail if the same operator was used multiple times on a single node
• fixed a bug that caused an error in the generation of unique variable names on nodes with more than 10 operators defined on them
• fixed a bug that caused CircuitTemplate.clear() calls to not clear all attributes on a CircuitTemplate instace, causing issues with multiple calls of CircuitTemplate.get_run_func
• updated the fortran backend to work with the recent changes to the numpy.f2py module for generating a modulate that can be imported into python from a fortran file
• fixed a bug in the ComputeGraph class of computegraph.py that caused function names to not be updated properly for backend-specific function definitions