Useintest

Added
- Ability to set environment variables for Consul service.

Changed
- Point at which Consul is declared ready to use.

Added
- Support for starting/stopping service inside a context manager.

Changed
- Consul service controllers now create specialised `ConsulDockerisedService` services.

Removed
- Support for `CouchDBLatestDockerisedServiceController`.

Added
- Pre-defined support for Consul.
- Configured for PyPi.

Changed
- Removes containers once stopped.
- No longer gives a warning if the library over-cautiously attempts to stop a stopped container.

Added
- SSH key helper for GitLab.
- Ability to define detectors that get the model of the service as the second parameter, which they could use to
interact with the service directly.
- Ability to easily override the default, logging based startup monitor via a new `startup_monitor` parameter.
- Pre-defined support for [Bissell](https://github.com/wtsi-hgi/bissell).