This can be used to inform callers that the operation is cancelled.

Check for operation status when streaming operations.
Allows client to catch a cancelled job.

Removed state machine. Will help with #66.

This will describe and configure hardware.

Also move `bot_session` to simply `session`.

This will contain the information about a running task
and lease.

This will manage the Tenant objects.

Also Moved bot_interface.py to interface.py.

Also moved the initialisation of these variables to
the `__init__` of `session.py`.

Also adds cancellation tests.

Mostly due to removing the state machine in the BotsService

#135

#135

#135

This turns Server.start() into a blocking call!

#135

#135

#135

Useful for tests, when port number is not determined beforehand.

#135

#135

#135

#135

This patch allows filtering the log records that get printed to stdout
and stderr based on their domain name using the BGD_MESSAGE_DEBUG
environment variable. A comma separated list of domains is expected:

  BGD_MESSAGE_DEBUG="buildgrid.server.cas,buildgrid.client.cas"