change default from mocha to tape

Tape is a nicer default then mocha 

The following now use tape:

 - rt/tia
 - rt/cerebro-client
 - uber/build-changelog

Reasons for tape:

 - can run programs with `node`
 - supports TAP out of the box
 - works cleanly in browser + node
 - has low implementation complexity
 - no globals
 - has `test.only()` feature to run a single block
 - has modular reporter with `tap-spec`
 - well maintained (has zero open issues)

cc @jcorbin @sh1mmer