Stable/0.3: fix x-position bug of bar plot in plotting results

[chensgit169]

The former function plot_probabilities() use indices of states as x-position, this is ok when full results are plotted. Yet when setting full=False, it works incorrectly. Consider the following example:

inds = np.array([0, 128, 256, 384])
probs = np.array([0.25, 0.25, 0.25, 0.25])
basis = ['000000000' '010000000' '100000000' '110000000']
plt.bar(inds, probs, tick_label=basis)
plt.xticks(rotation=40)
plt.show()

This is purely a problem of plotting.