namespace cleanup: add plot_ prefix to visualization function and deprecate old functions.
import/namespace cleanups
pep8 fixes
use plot_fock_distribution instead of fock_distribution also internally
import plot_... functions
pep8 fixes
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
bug fix in plot_energy_levels function dispatch
fixed integer/float bugs
added plot_wigner and fixed minor bugs
added import of plot_winger in init file
Merge pull request #102 from jrjohansson/patches-visualization

Patches visualization
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