Port the "Locations in the Neocortex" paper code to work in Python 3

[mrcslws]

This change ports the "Locations in the Neocortex" (Columns+) code from htmresearch and gets it working in Python 3, using nupic.research.core.

[mrcslws]

Here are the figures. (The paper used 5 repetitions and plotted the mean. For these sanity tests, I just ran 1 repetition of each.)

Figure 6

Figure 7

Figure 8

Figure 9

Figure S1