added MIT license

This pull request proposes that basiccoin add the MIT license, a non-restrictive open license. Without adding this or some other open license, the basiccoin code cannot be used in any other projects, and people would not be legally allowed to fork it to create new currencies (indeed, they may not be legally allowed to even use the software itself). The MIT license is the [same one] (https://github.com/bitcoin/bitcoin/blob/master/COPYING) that bitcoin is released under. Fixes #3.