Add connect/disconnect methods to otultra2 and send \x11\r on connection.

The otultraeasy requires explicit connect/disconnect so implementing
this before is helpful.
common: fix namedtuple usage to allow for optional parameters.

The otultraeasy does not provide comments or meal indications.
Initial support for OneTouch Ultra Easy glucometers.

The driver is fully functional but requires proper documentation and
testing.