Update version to 1.99.2
Add circat.yml to setup file
Complete Daq driver documentation.

Add examples and driver graph.
Minor fixes to the documentation

- Add return value to graph reading example.
- Mention support for Designer to index.
- Mention support for SCPI.
Bugfix Watlow ctrlr

- Fix layout bug.  This fixes the error reporting that self.ui already
  had a layout.
- Fix None passed to combobox error.
- Make sure we can read the rate on start up by setting
  global_.rate_init to 1.
Fixup VirtualDaq
Make Context class derivable.