zoom fit

Fixed wonky fit behavior reported
https://github.com/tweecode/twine/issues/28

added line 676
self.zoom(1.0)
Jonah, Sugarcane and Responsive fixes.

* Fixed a bug in my fix of the "macro" formatter lookahead regex -
sorry, it's good now.

* Unminified all the engine JavaScript in the header HTML files using
jsbeautify.com, primarily to make subsequent source diffs more readable,
and secondarily to make development less confusing.

* Moved previous fixes into Responsive:

-- Missing String.unDash

-- Greater-than signs in macros

-- Passage.prototype.render: data-tags attribute only added if tags
exist.

-- Passage.prototype.excerpt fix

* Added fixes to Sugarcane and Responsive:

-- Revised the Rewind menu so that it backtracks through state.history
instead of recalculating the game state using the URL hash.

-- Revised <<back>> and <<return>> so that they backtrack through
state.history instead of recalculating the game state using the URL
hash. This means, among other things, that random numbers used earlier
in the story won't be rerolled by <<back>> or <<return>> usage.

-- Also, <<return>>'s code has been merged with <<back>>'s, since their
only difference is that <<back>> rewinds the game state (and has a
different name).

-- The Responsive syntax for <<back>> has been merged into Sugarcane as
well - "label" and "labeldefault" parameters are valid. Moreover, they
can now be used alongside "steps" and "passage name" parameters, in
either order.

-- Updated Responsive's Passage.prototype.render to match recent
Sugarcane fixes.

* Fixes specific to Responsive:

-- Fixed the broken Rewind menu (missing "snapbackMenu" div and CSS
styles).

-- Fixed the Modernizr credits link.