quantum_state_sim

This provides a quantum simulation abstraction tool to simulate quantum circuits.
Uses the state vector simulation method.
Memory consumption is 2 * 8 * 2num_qubits bytes. For example, simulating 25 qubits cost ~537 MB.

The following gate operations are implemented:

• Pauli X gate
• Pauli Y gate
• Pauli Z gate
• Hadamard gate