0.9.8 String Escaping

Added

• Handlebars::escapeExpression() method (equivalent to the Handlebars.escapeExpression() utility function in Handlebars.js).

Removed

• Unnecessary $escape parameter on SafeString constructor.

Fixed

• Nested else if validation (fixes zordius/lightncandy#313).
• Escaping multiple double quotes (fixes zordius/lightncandy#298).
• Single-quoted string parsing and compiling.