Add the climate model

[frodre]

Add the climate model created by Judy Twedt and Hansi Singh.

• Add a section of inputs for basic planetary characteristics for model
• Connect climate model running to a 'calculate' button
• Use holoviews/geoviews to serve the plot of planetary temperature

[frodre]

Finished encapsulation of the Star/Planet sim, and the North climate model. I don't know if I can get
holoviews to work for this though.

addmodel: 7a4df24

[frodre]

We have opted for a general habitability calculation using a grey atmosphere instead of the energy balance model as proposed. This is mainly due to the difficulty of making projected pcolor plots of a globe. Will probably revisit this at a later date.