Autolinking of Twitter handles can now be disabled by passing `twitter: false` as a property of the `options` argument.
Autolinking of email addresses can now be disabled by passing `email: false` as a property of the `options` argument.
Autolinking of standard URLs can now be disabled by passing `urls: false` as a property to the `options` argument.
Moved modular link type tests to their own `describe` block.
Added some additional unit tests.
Added a new `callback` option allowing for very comprehensive control over the final HTML. The included additional test (singular...) is extremely basic, but I'm a little pushed for time right now - it at least shows that the option *works* to some extent...
Merge branch 'modular-link-types'
Merge branch 'complex-callback-option'

Conflicts:
	src/Autolinker.js
	tests/AutolinkerSpec.js