added in refreshing the bots after every swap from arena mode to edit mode.  Every time we move from edit
mode, the arena is cleared out and all bots are added back in.

This is mostly for wheels and other box2D attachments, so that they can get added into the box2D model after
they have been placed on the bot.
Merge pull request #38 from galaxykate/jpagnutti-botRefresh

bot refreshing