Proper documentation

[countvajhula]

At the moment, Symex doesn't have a single repository of documentation. There's:

• the README which contains some basic information, configuration, and tips, and a keybinding table
• the DSL-Docs.rst file which contains basic documentation for the DSL
• the Animated Guide which functions as a visual introduction and tutorial

It would be great to have:

• integrated and thorough documentation located at a definitive source (e.g. Emacs's Info system)
• an interactive tutorial (eventually)
• developer documentation, including Git collaboration workflows (e.g. capturing things like this comment)