Add Travis configuration

[rtsisyk]

• Add a Travis configuration file:
  • Module must be build without errors
  • Script should install tarantool and tarantool-python from our repos
  • Script also should run tests
• Update README to add Travis badge

https://github.com/tarantool/tarantool/blob/master/.travis.yml and https://github.com/tarantool/http/blob/master/.travis.yml can be used as examples

[rtsisyk]

Blocked by tarantool/tarantool-python#36