Fill Up The Hole 0.08

• Majority of the changes were on the upgrades.
• Each building can now be built once unless more yellow shard are put in the node.
• Fixed some issues.

I'm still working on setting good cost for each upgrade and finding the right balance between permanent and temporary upgrades. I'll continue fixing issues, but my focus for the next version will be on adding more utility to certain buildings (e.g., the power building isn't very useful right now).