[TRAVIS] added libsrtp to be built with pjsip

• [TRAVIS] added libsrtp to be built with pjsip
• [DOCKER] updated local testing environment
• [NPM] updated package-lock

v0.0.1

Fixed bug and updated testing on travis-ci (#1)

* [BUG] account config was not enough to make an account
* [README] updated
* [BUG] fixed location of sound files
* [UPDATE] check the state of registration whenever making call
* [TRAVIS] use the latest node and LTS for testing