Dcos-shakedown

Features:

- `--stdout-inline` now passes the `--capture=none` (`-s`) flag to
PyTest, enabling streaming inline test output
- `private_agents()` and `public_agents()` PyTest decorators to
replace old explicitly-named (eg. `private_agent_2`) decorators
- `wait_for_mesos_endpoint()` method waits for a specific endpoint
to return `HTTP 200`
- new ZooKeeper method `get_zk_node_children()`
- new master methods `get_all_masters()` and `get_all_master_ips()`
for clusters deployed with multiple master nodes

Fixes:

- updated `test_dcos_command` test to work on new release of CoreOS

Features:

- stringified `wait_for` predicate info for better debugging and
understanding of which predicate and which values

Fixes:

- trailing slash added for `/service/{}/` calls
- turn off noisy option in `wait_for`
- documented how to use `DCOS_CONFIG_ENV` for parallel execution
- `wait_for` log previously ignored exception during waiting when noisy
enabled

Features:

- DC/OS Enterprise Edition version-checking
- `ee_version()` method, `strict`, `permissive`, and `disabled`
PyTest security mode markers
- bumped `dcoscli` version to `0.4.16`

Features:

- ability to skip tests based on required resources, DC/OS versioning
- eg. `pytest.mark.skipif('required_cpus(2)')` and `dcos_1_9`
- support for deleting leftover data following persistent service
uninstall (ie.a `janitor.py` shim)
- `delete_persistent_data()`
- `destroy_volume()` / `destroy_volumes()`
- `unreserve_resources()` / `unreserve_resources()`
- command methods now allow disabling output and/or raising on error
- marathon methods add `delete_app`/`delete_app_wait` for a specific app
- package install methods support waiting for service tasks to start
running, additional logging
- package uninstall methods add support for deleting persistent volumes
after uninstall
- packge repo methods support waiting for add/remove repo to complete,
check for a changed package version
- service method function for deleting persistent volumes
- service method support waiting for task rollout to complete
- service method verifying that tasks are not changed

Fixes:

- marathon methods fix unused `app_id` when checking deployment
- `hello-world` package (previously `riak`) now used to test
`test_install_package_with_subcommand()`
- spinner-related fixes:
- while a spinner is polling, print the spin time and any
ignored exceptions by default
- don't drop the original stack when rethrowing exceptions
- return the result of the spin at the end of `wait_for`,
allowing passthrough of the predicate return value

Features:

- split `requirements.txt` and `requirements-edge.txt` for
building against `dcoscli:master`

Fixes:

- `_wait()` functions now wait on deployment, not health
- uninstalls now wait for Mesos task removal
- tests fixed for package installation and waiting
- improved error messaging when unable to connect to a host

Features:

- new cluster functions `get_resources`, `resources_needed`,
`get_used_resources`, `get_unreserved_resources`,
`get_reserved_resources`, and `available_resources`