There's too much happening in DocFormatter, moving these things
to separate classes, will make it a little bit cleaner.

For now implementing two types:

    {@video html5 some/url.mpeg Comment...}

    {@video vimeo 8791231354 Comment...}

With future possibility of allowing users define their own types.

This allows easy embedding of videos to guides (and even to class
docs if there should be such need).

For now only supporting Vimeo videos, just like the separate videos
page:

    {@video <vimeo-video-id> Some comment}

Previously when class Foo happened to be listed before Foo.Bar,
the Foo node was created and Bar added as a child to it, but
Foo was left to be a leaf node, which meant its children were
invisible, making the class-tree look broken.

To please our asian fellows.

Previously it may have happened, that multy-byte characters got
breaken from the middle, resulting in invalid characters. Now
we're using the unicode support in regexes to count chars correctly.

A great resource for UTF-8 support in Ruby 1.8.7 is found here:
http://blog.grayproductions.net/articles/bytes_and_characters_in_ruby_18

Also remove some useless comments.

The search no more assumes we are dealing with classes and members.
We just supply the short and full name of an item, whatever it is.

A first step in making possible to include guides and other stuff
to search.

Exposed Docs.History#navigate method to have an easy way to navigate
to any page by URL.

Having a notification makes it obvious that something happens right
when clicking the checkbox.  Otherwise one has to wonder if he needs
to post a comment for the checkbox to take effect.

The extjs/ subdir in JSDuck output is now dedicated to the ExtJS
which the Docs app itself uses.

For examples to work, a separate directory (by default extjs-build/)
should be created and referenced from eg-iframe.html and examples.

Instead of hardcoding ExtJS and Touch examples paths, the
--examples-base-url option determines where icons are located.

The important change is that examples.json file now has to define
icons relative to --examples-base-url (this was the case for Touch,
but not for ExtJS).

Example title and description fields are now also correctly convered,
independent of url being absolute or not.

Auto-created example name no more contains the --examples-base-url
in it.

Variable 'comment' is already a parameter, no 'var' needed.

Simplify calls to #warn by moving more logic inside it.  Now with
the calls to warn taking up less space, other code comes easier to read.

Previously #membername always had to be prefixed with full class name.
Now one can just use member name to reference member from current class.

The default value is now specified in config.json in touch repo.

Not really used for now and only confuses things in this already
cluttered file.

In touch2[export] task make use of SDK/touch/docs/build-* files.
This removes the need for the whole rewriting process of welcome and
eg-iframe pages.