Documentation improvements based on user feedback

[dbrakenhoff]

From the user day, I gathered that it would be nice to have a bit more guidance for newer users on the documentation page, and extra tutorials and how-to guides that help new users. The contents here might already exist in the current set of notebooks an examples, so in some cases it might be more a case of restructuring, but this is the list of stuff I came up with:

• Some guidance on the main documentation pages that tell (new) users good places to start.
• An introductory notebook that explains the analytic element method?
• A notebook that helps users let go of their Modflow brain (and delusions ;))
• A notebook on steps to check your model (e.g. computing integrated fluxes, plotting heads along lines, contour plots, particle tracking, ...?). Could be tied to the eventual development of automatic refinement methods.
• Notebook on linesinks explaining among other things the order and splitting up the elements into smaller segments
• Guidance on particle tracking + capture zones, what parameters should the users change? Are the defaults any good, or are they very problem dependent?
• Perhaps an FAQ page with short answers (and links to longer notebooks) to common questions?
  • What do the different top boundaries mean?
  • What is the Constant or Reference Point?
  • What does the order of a linesink mean?
  • My model is slow, now what?
  • My model won't solve, now what?
  • How do I model an unconfined aquifer?
  • ...

And there's probably some stuff that I may have forgotten. Feel free to add any suggestions below.

This stuff is a lot of of work, so I'm hoping this can partly be achieved through community effort. It's a nice opportunity to contribute something (however small) to Timflow, either through Github, or responding here with useful additions, or snippets to add. So any help is greatly appreciated!