Unable to run tests on Travis

[kimburgess]

Execution of test and coverage reporting on Travis not currently working due to incompatibility with the pre-compiled version of Edge with the repo and the Travis environment.

See output at https://travis-ci.org/acaprojects/skype-native/jobs/234352856

Likely need to build edge as part of the project build process. This will also remove the need to depend on both edge and electron-edge.