Add Picture to Customers, Vendors, and Activities

You need to have imagemagick installed for some of the features to work ````brew install imagemagick```` and if you want to deal with pdf uploads and the test suite you need GhostScript ````brew install gs````. I don't know if I've ever used GhostScript directly, but I also haven't tried running anything without it installed. I would just install it either way. 

Right now the images that can be uploaded are automatically scaled down to 300x300 or 100x100 (but we can change that if we want). I was trying to get the cropping to work but it required some weird jQuery and I may need someone's help going over that. There are no tests for this as of now, but I can write some if needed.

I merged the latest from the development branch yesterday, so it should merge back into development just fine if there aren't any issues.