4.1.1 Code base cleanup

• Support nested grouping of guides/videos/examples.
• Basic mobile-friendly version of docs.
• Auto-detection of @chainable tag.
• Hide parameter types in method signatures.
• Return values of constructors now default to the owner class.
• Remove 'api' export type (--export=full can be used instead of --export=api).
• Remove --stats option. The statistics page wasn't of much use.
• Fix crash in IE8 when loading a class into view.
• Upgrade embedded Esprima.js to latest version.
• Large refactoring of how class members are internally stored.
• Lots of other refactorings to improve JsDuck code base.
• Rewrite of comments backend (not available for public use for now).