[WIP] Tokens transformators

Very, very early proof of concept about transforming tokens (resolve #531).

- [X] add `T_ARRAY_TYPEHINT` for `T_ARRAY` used as typehint (fix #542)
- [ ] create `T_CURLY_CLOSE` for `T_CURLY_OPEN`
- [ ] create `T_DOLLAR_CLOSE_CURLY_BRACES` for `T_DOLLAR_OPEN_CURLY_BRACES`