documentation improvments

* added a bit more where it was not clear from the documentation where values like PLACEID were coming from
* added $ in front of shell command examples
* adjusted spacing/indentation so that github's markdown will show commands as such
* added `backticks` on commands,  variables, values
* made examples all use San Francisco for consistency. Note that currently the documentation provided when running `make` commands is for New York, which was confusing for a moment (we might want to change that later)