Fix API breakage -- important

Fix broken due ot 411 Content-Length error now sent by Nexmo backend
Merge pull request #9 from bpilot/patch-1

Fix API breakage -- important
bumped version number
Update README.md

added opts to sendmessage
bumped version to 0.3.4
Support for Nexmo's Voice APIs
Fixed parameter names and added voice commands to examples
Added Call API
Merge pull request #12 from akuzi/master

Nexmo Voice API - Thanks for the pull request
buming version to 0.4 with support for voice api
fixed the version number
updated docs