added support for 1 and 2 gates to act on larger qubit spaces
added gate_expand_3toN for expanding 3-qubit operators to N qubit spaces
fixed bug in __init__ of Register class
code cleanup
fixed issues in gate_expand_2toN and gate_expand_3toN
added unit tests for some gates and for gate expansion from 1,2,3 qubit spaces to N qubit spaces
Allow dims elements to be np.int in addition to in (happens when Qobj.permute is called)
fix bug in Qobj.norm() for kets with only zero (happens when (psi1 - psi2).norm() if psi1 == psi2)
added the N-qubit Hadamard gate
fix docstring typos and pep8 issues
fixed variable-scope bug in gate tests
Merge pull request #103 from jrjohansson/gates-patch

added support for 1 and 2 gates to act on larger qubit spaces