Started fixing Agilent docs.
Added to introduction.
Started refactoring into an enum.
Continued refactoring, making minor improvements.
Started work on integrating Agilent 34410A with new ABCs.

Agilent34410a is now a subclass of SCPIMultimeter.
The class probably doesn't work right now, as this is a WIP.
Merge pull request #2 from cgranade/dev

Merged in changes to dev branch from cgranade.