Test runner modifications to specify test lists and tags
Swarm tests moved to integration-level tests, not run by default.  This
implements the -i flag to run_tests.sh, -e flag to run test lists, and -m flag
to specify tags.

Options for running long-running swarm tests:

    run_tests.sh -i
    run_tests.sh -e tests/engine.testlist
Updated copyright notice and documentation
Merge remote-tracking branch 'upstream/master' into testlist_runner
-e renamed to -t, tests/engine.testlist renamed to tests/swarming.testlist
Merge remote-tracking branch 'upstream/master' into testlist_runner
Run all tests in travis, using long-format CLI options
Merge pull request #218 from oxtopus/testlist_runner

Test runner enhancements