gcm analog needs to be simplified

[dhruvbalwada]

At the moment the gcm-analogue.ipynb has some text in the last two sections that is irrelevant to the main message. This should be either deleted or incorporated somewhere -> I think the errors discussion needs to go to the key_aspects notebook and the stochastic discussion needs a seperate notebook (if it is self contained).

[dhruvbalwada]

• I have now removed the last two sections (sources of error and stochastic parameterizations).
• The important parts of sources of error have been added in part to the next notebook, gcm-parameterization-problem.
• The part in gcm-parameterization-problem on sources of error has been removed, as it was just a long winded description of what was was present in gcm-analogue.
• The stochastic parameterization part from gcm-analogue has been removed, as it was reaching an inconclusive finale.
• If we need to reintroduce any of the removed parts at some later time this can be done, as the older version of both thees notebooks are kept as copies in the notebooks folder.