avoiding 2 of the same check from running concurrently

- each check now sets a bit to 1 when it begins and back to 0 when it ends (in the `Measure` call)
- `measurer` now checks the bit and ignores the check for that scheduled run if it's already running

This PR also removes unneeded Godep files:
- source files in the `_workspace` and the 
- the `Readme`