Pheromone is set once after each ant completes a tour and decayed only then.

Added pheromone and distance importance attributes
Changed default distance/pheromone importance and configurations:

-Enabled/disable pheromone display
-Default pheromone configuration
-And speed shows infinity at max
Ensured all edges have a chance of being picked (albeit small)
Added mutation chance to pick a random edge

This should help prevent premature divergence, especially when the graph is
changing on the fly
Also changed default tours to be more precise.
Better scaling of tours. Uses original city coordinates, and scales view

Also fixed logic so cities can be removed correctly.
Fixed small bug removing cities