Add support for BINARY field in MySQL
Needs tests in order to merge.
 You can add tests to the `test_fields.TestFieldTypes` or you can just create a one-off test-case. Either is fine.
 Done. Apologies for the initial lack of tests, I got lazy!
 Those tests don't actually test the binary field.
 Ah crap, it looks like my cherry pick didn't apply properly due to lack of concentration, will get this fixed in the morning, sorry
 Done, I'm pretty sure this is fine but any problems let me know
 Thank you!

See #801
