new Formula: dropbear ssh client and server

please review this new formula, are the tests ok?
It should install to a Cellar path, like /usr/local/Cellar/dropbear/2014.65/bin. `prefix` will have the value  /usr/local/Cellar/dropbear/2014.65. Homebrew will then automatically symlink the files into /usr/local after installation. The upgrade mechanism depends on this and Homebrew supports prefixes other than /usr/local.