Ability upgrades and tweaks

The server should add the ability to upgrade your abilities you receive by leveling up using money, just like furnaces. Each would cap out at your current rank, and each level increases ability duration and effectiveness. This is a feature implied in the game already, but just hasn't been added in yet, as all abilities are displayed as "Level 1"". Also, the Minions ability should make al blocks minions mine go directly into the player's inventory, as having to pick up Minion Drops renders it completely useless. This should add value to the abilities for players toward the late and endgame better. If anyone else has any further suggestions on new abilities or changes to the current ones, feel free to post them here. Hopefully, a dev reads these.