Design state dependency specifications

[xandkar]

Need to be able to express:

• groups of sequentially-dependent tests
• groups of independent tests (to be executed concurrently)
• any variation of a dependency between a test and a group, such as:
  • group => group
  • group => test
  • test => group
  • test => test

Scheduler, before executing, should check for and abort upon finding a circular dependency.

Before execution, inferred schedule should be stored in DOT format.