handle PUT/POST/DELETE to /data/fs/[path] (Fixes #140)
a useful EncodeJson[Path]
parse quoted identifiers (with double-quotes)
string literals now have to use single quotes, per the SQL spec
double and single quotes can be escaped by repeating them
no other escapes implemented, per the SQL spec
handle fancy collection names in generated JS
generate nicer temp names

In the sense that they don’t require special handling in the mongo
shell.

Also treat names starting with ‘_’ as not nice, since the shell seems
to feel that way.
Tighten up PUT/POST semantics

PUT now atomic.

POST captures and reports partial failure.

Both take their input as a stream of values.