Downgraded Koa Cors version - issue with Access-Control-Allow-Headers not being set correctly
validated that port is numeric fixes #201
Merge pull request #233 from jembi/tcpport

validated that port is numeric fixes #201
Merge pull request #232 from jembi/koa-cors-update

Downgraded Koa Cors version - issue with Access-Control-Allow-Headers not being set correctly
merged with current master