Added showHeaders option to disable header output, enabled by default. Test cases added too.
Merge pull request #16 from four43/feature-disable-headers

Added showHeaders option to disable header output, enabled by default. T...
npm install vs update in travis hook
Use wcwidth vs wcwidth.js.
Release 1.2.0
Always prune before test.
Fix reference to wcwidth.js
Release 1.2.1