Use ruby objects for thrust configuration
Move spec files to match production code layout
Use require_relative in version.rake
Fix module namespacing
Backfill tests for Thrust::Executor
Backfill tests for Thrust::UserInput
Inject dependencies into Autotag tasks
Fix Autotag::List (was using configuration hash)
Fix failing tests in ExecutionHelper spec

Looks like system() before 2.0 cannot execute bash built-ins, and fails
with status 127 (Command Not Found).
Merge pull request #29 from cbguder/refactor

Finish refactor