This updates the documentation to mention that:
1. a lot of data may get sent to the docker daemon if there is a lot of
data in the directory passed to docker build
2. ADD doesn't work in the absence of the context
3. running without a context doesn't send file data to the docker
daemon
4. explain that the data sent to the docker daemon will be used by ADD
commands
This should make previewing documentation easier.
Also updated the Makefile to now copy the theme dir into the _build/website/ dir. Make connect and Make push work.