add TODO file
WIP
split up gate tests
remove command-line interaction

need to re-think this and it's using old classes that no longer
exist
test resize register bad num_qubits / qubit_nums

test that you cannot resize a register to n qubits without
specifying the exact number of qubits that the resized gate
should act on
test generate bases vectors
add generate bases vectors method
improve generate bases vectors

one less call to reverse() by looping in the opposite direction
and slightly clearer implementation
fix inconsistent loop counter
test filter bases
add filter bases

filtering bases is a step towards being able to resize a gate
so a gate of size n can be applied to a qubit system with number
of qubits m such that m > n