0.1.0 - full implementation, but slow

This is the first release (pre-1.0) of this parser for the KDL document format.

It passes all tests for the JS and Rust implementations, give or take a quibble about the spec.

It's... slow! For now! The underlying library, Parsica, has yet to focus on speed, and there are likely some optimisations (memoisations and the like) that this library can perform on top of that. The aim is absolutely to increase parse speed significantly, although it will of course remain a PHP implementation and therefore will be less performant than a parser in e.g. Rust.

Please report any issues found!