Pre-requisites required to build and test
These are the pre-requisites that are required to build and test 'flow':
- rust toolchain (
rustup,cargo,rustc, etc )- with 
wasm32-unknown-unknowntarget for compiling to wasm clippyfor checking coding best practices
 - with 
 zmq(Zero Message Queue) librarygraphvizutilities for automatic generation of SVG files for the book
For building the book:
mdbook and the mdbook-linkcheck plug-in
Installing pre-requisites
You have to install rustup, cargo and rust toolchain yourself. I decided to stop short of futzing with people's installed toolchains.
There is a Makefile target config that will install the other dependencies:
make config
That will add the wasm32-unknown-unknown target, clippy, graphviz, mdbook and mdbook-linkcheck.