'Special Agent 'Pros are permanent upgrades for Special
Agents, they are upgraded by placing them a certain number of times.
The amount of times placed to receive the pro upgrades are as follows:
Tribal Turtle: 50
Bloonsday Device : 20
Meerkat Spy : 50
Bloonberry Bush : 50
Beekeeper : 40
Angry Squirrel: 50