Add one line summary to count tests passed/failed/skipped

[jeremybaumont]

Hello,

My team members and I, really like your project :-) thank you for adding colors to go test output.

We really like to keep the standard output of go test tool, the only 2 things that we would love to add were the colors (solved with this project) and a summary line counting the number of tests passed, skipped and/or failed.

We were wondering if you would consider adding this summary line at the end of the output that counts the number of tests. I'll push a PR to materialize what I mean.