This PR makes the use of project IDs a configurable option. It also changes the default name for the field from "safe project id" to "project id", and introduces alias checking so that uses of "safe project id" are handled correctly.
The alias checking is only properly set up for mandatory core fields, but hopefully has been written in a way that should be extensible to other fields if there are other places we want to use aliases.
This PR makes the use of project IDs a configurable option. It also changes the default name for the field from "safe project id" to "project id", and introduces alias checking so that uses of "safe project id" are handled correctly.
The alias checking is only properly set up for mandatory core fields, but hopefully has been written in a way that should be extensible to other fields if there are other places we want to use aliases.
Fixes #50