Travis build

Travis CI file

See merge request !7

Zone cut per query

Zone cut is resolved separately for recursive side queries.

See merge request !6

this fixes resolution of multi-level queries, when a side query
encounters a nameserver that requires address resolution

Test

See merge request !5

Integration tests

Server-independent integration test case parser/player written in Python.
Currently the test is able to parse a subset of unbound test cases as described in:
- http://www.unbound.net/documentation/doxygen/replay_8h.html

The test cases are BSD licensed.

The Knot resolver mock context overrides the library calls to message sending functions,
redirecting them to the server with scripted answers.
The scenario can do following things:
- Simulate system time
- Provide scripted answers
- Send queries, compare responses

See merge request !4

this is a workaround, as the server may not support stub zones.
in that case it may ask a different root server than we have in
configuration

it's not running while we're in the C code anyway because of GIL