Add magic slot to variables.
Add magic slot to strings.

Could add it to all variables but we only need it on strings for now
(to stash compiled JSONPath expressions) and putting it inside the
string means it benefits from the copy-as-reference behaviour of
strings. It's also available to arrays if necessary - by virtue of them
being string based.
Rename private symbols.
Ignore tags.
JSONPath toker.
Scan jd_path.h
Message was correct. Doh.
Test coverage for jd_get_idx outside scope.
Ignore TAGS.
Basic parser skeleton.
More parsing.
As if it matters...
Not just for keys...
Iterate hash keys.
Extraneous magic.
Accessor for magic.
Merge branch 'master' into jsonpath
JSONPath WIP.

Attach compiled path to string's magic.
Test coverage for string magic semantics.
WIP snapshot.