Some tests working pheremoneDecay() not

Got some tests working after changing how pheremones were stored.

point.pheremoneDecay() is not working due to dict changing during
popping.
Got point.pheremoneDecay() working

Got it to remove items from list. Clunky but works. Need to implement
oldest first removal.
Old tests passing

Tests that were broken due to changes in point class all seem to pass
now.

Left with purposefully broken tests that need code writing.