Fork and add 'USB Image Writer' and 'USB Formatter' in the next UbuntuMATE

[stevecook172001]

This is the one I use. It works for me on both UM 14 and 15:

mintstick_1.2.2_all.deb

https://launchpad.net/~tsvetko.tsvetkov/+archive/ubuntu/trusty-backports/+files/mintstick_1.2.2_all.deb