Fill Up The Hole 0.07

The upgrade\buying system was a bit complicated, so all permanent upgrades have been consolidated into a skill tree style UI. Upgrades that last during the life of the buildings will remain in the building's info popup. Hopefully this will make it easier to understand/use.

The "Store" building has been removed as it was no longer needed with the introduction of the skill tree.

The new skill tree layout allow for more interesting ideas for development. Currently, it reflects the upgrades that were already available. I'll take some time to change the skill tree and add new nodes.