Update readme with codecov info and cli -h output
Update readme with codecov info and cli -h output

evanlucas/node-tap,iarna/node-tap,myndzi/node-tap,tapjs/node-tap,myndzi/node-tap,isaacs/node-tap,tapjs/node-tap,jinivo/marhert,strongloop-forks/node-tap,iarna/node-tap,strongloop-forks/node-tap,evanlucas/node-tap,isaacs/node-tap