Manual testing plan for Valence

[jimblandy]

We should have a script for manual testing of Valence, to catch regressions in connecting with real devices that aren't practical to test automatically.

The script should cover all combinations of:

• host devices, running the user interface
• target devices, running the debuggee software
• debuggee software
  for some prescribed set of operations.

Mozilla pays by the hour for this testing, so we should weigh the value of each test with that in mind.