Revert "Fixed parser so that square brackets count as delimiters"

This reverts commit 389396bd7aa1d9cbf7d473908612a4695c7cbcaf.

This breaks stuff with no gain re. the specification.

I think the query parser should ultimately tokenize everything, but that would be a rewrite.

Fixes https://github.com/phpcr/phpcr-utils/issues/131