Only match on innermost bracketed tokens

`{hey {joe}}` will match `joe` and not `hey {joe`

Signed-off-by: Christopher Rogers <chrissrogers@gmail.com>
Allow brackets with strange syntax to tokenize

This allows brackets containing odd syntax that would otherwise break a dynamic function e.g.: `{...}`, `{1}`, `{+}`, to be matched or ignored.

Signed-off-by: Christopher Rogers <chrissrogers@gmail.com>