Refactor somewhat so that escapeId() works right

Refactor somewhat so that escapeId() works right

r45267 commented out the logic prohibiting numbers and so on at the
start of id's.  I've uncommented this logic, but passed 'noninitial' as
an option to escapeId() in all necessary circumstances.  Shouldn't
change behavior, this is to simplify some further work I'm about to do.