fixed error due to missing color card
update output format to the new YAML structure
Have all arguments come from the config file.

We add start datetime, end datetime and time interval to the configuration
file.
* util/pipeline_demo.py (general): Add new arguments to a global dictionary
"general".
(Comments): Update comments to reflect what we expect from the configuration
file.
Include a visualize switch in config file.

* util/pipeline_demo.py: Simplified the argument parsing. We now look for
visualise in the yaml file. We default to no visualization.
Add general pipecomponent Exception

The new exception should be used when there is an unrecoverable error in any
of the pipeline components (e.g. when tray detection does not work).
This is a way to handle things that are not yet implemented.
* timestream/manipulate/pipecomponents.py (PCExBrakeInPipeline): New general
pipeline error class.
* util/pipeline_demo.py (visualise, result): When encountering a
PCExBrakeInPipeline we output message and continue