handlebars: fix Property tests
handlebars: update tokenizer spec tests

Bring HbTokenizerSpecTest back in sync with Handlebars tokenizer spec
tests ('spec/tokenizer.js')
handlebars: add support for subexpressions

See https://github.com/wycats/handlebars.js/commit/b09333db7946d20ba7dbc6d32d5496ab8295b8e1