enable Travis integration
add Coveralls support for test code coverage monitoring
added yast_stubs.rb with Yast stubs

to not require "yast" at tests
(Yast is not available at Travis)
adapt the tests to not require "yast"

- stub require "yast" call
- stub all Yast calls
added README.md with status badges

- Travis status (build passing)
- Coveralls status (code coverage percentage)
- CodeClimate (code quality)
- License badge
- Development status badge
Merge pull request #25 from yast/travis

Travis integration