v2.3.1

Minor

• #643: Writer.prototype.parse to cache by tags in addition to template string, by @raymond-lam.
• #664: Fix Writer.prototype.parse cache, by @seminaoki.

Dev

• #666: Install release tools with npm rather than pre-commit hook & Rakefile, by @phillipj.
• #667, #668: Stabilize browser test suite, by @phillipj.

Docs

• #644: Document global Mustache.escape overriding capacity, by @paultopia.
• #657: Correct Mustache.parse() return type documentation, by @bbrooks.