Squashed 0944d8a (check_timeout) into one commit

Hi I have squashed it all into one commit - let me know which you prefer and I'll kill the other (I prefer this one if you don't care).

Once one or either is merged, then I have some fixes for the bugs that where found to submit.

Squashed 0944d8a (check_timeout) into one commit:

Simplify and expand tests, adding tests for:
* timeout conditions
* unreachable hosts and routes
* open and unused ports

Added test/setup_ubuntu.bash to setup unreachable host, route,
and confirm we can still use telstra.com as a black hole
for pings and tests for ports 7, 22 and 1001

Refactored tests to line up with existing example in external

Add extra rvm versions;
Add IGNORE_HTTP_PING_DOES_NOT_WAITS_FOR_RESPONSE_BUG and
IGNORE_HTTP_PING_DOES_NOT_TIMEOUT_BUG to test those bugs with
failure allowed;

Reorganise .travis.yml to make intent clearer

Speed up timeout tests

Give more details on failing tests