added documentation, redid class hierarchy.
wip, more classes added, chained configuration
trying out new inheritance thing
can create channel object

problem was in my understanding of super. Apparently the two argument
form returns an already bound version, so it adds the self argument. I
was not taking that into account and my arguments were interpreted
wrong.
analog voltage addition works, or appears to

Added AnalogInputVoltage functionality. It occurs to me that when a task
returns its channels, unless i happen to have created that class, I
cannot utilize the information. So, I need to add the ability to "fake"
create my class from the base down instead of the normal way around for
the case that the class exists and I do not need to call the C-API.

The problem there is that if I happen to have two classes representing
the same channel, there might be synchronization issues. Maybe I should
have a internal dictionary of created channels? That way, a call to
create a new channel of a given name will return that instance instead
of a new class.