Generated README should have project build commands first

[aantron]

Right now, the README starts with make switch and make build, both of which are unnecessary after template generation, and just make the user wonder if the deps aren't installed after all that automatic work during generation.

IMO the README should just recommend make, make start, and/or make watch. A separate section on updating deps should recommend editing the opam file and running make deps. It should be after tests and docs.