* intial docs and images to describe receiving a block and simple sync.
* add some more description text
* svg -> png
* updated simple_sync diagram to include sync_head
* rename "block head" -> "body head"
* wip - sync_on_form diagram (kill me now)
* tidy up diagram for "sync on fork"
* consolidate the chain docs
* add doc/table_of_contents, initial attempt, based on https://lists.launchpad.net/mimblewimble/msg00024.html
And explain and link to build.md about creating folders server and wallet manually.
* add Files in this folder (doc)
* rename headlines
* docs: extract code and directory structure to code_structure.md