Better dummy for test and better demo example for demonstration and d…

Switch to GOTEST_SKIPNOTESTS instead of the -skipnotest

Filtering out the flags and arguments are making it harder to maintain
the tool and we don't have comphensive testing to capture all the
significant failure modes. Switching to an environment variable.

Fix the colors broken by #23

Fix undefined c issue (#28)

Forward OS signals to go test (#15)

Remove the vendor directory and the dep support

Also, add the missing go.sum.