Upgrade to Meteor 0.8.0.1 (new blaze rendering engine).

Meteor release notes:
https://www.meteor.com/blog/2014/03/27/meteor-080-introducing-blaze
https://github.com/meteor/meteor/blob/release/0.8.0.1/History.md

A number of changes to support the new Blaze rendering engine; see
https://github.com/meteor/meteor/wiki/Using-Blaze for more details.

* No more {{#isolate}}, or preserve: these are not necessary any more;
they've been removed from our codebase.  The `preserve-inputs` package
has also been deprecated and removed.

* Rendered callback only fires once: this was the trickiest change.
In many cases we used an 'this.afterFirstRender?()' pattern in order
to only execute some code on the first render; these were easy to
inline and remove.  Other bits of code required more attention;
in two cases (`scrollHack` and `updateScrollSpy`) we added new helper
functions which would get invoked when the relevant bits of the page
were modified.  On the round and puzzle pages we added new `autorun`
computations that would update the title specifically when dependencies
changed.

* Conditional attributes with no value: we needed to rewrite our
`checked` attribute as `checked={{isChecked}}` as the Blaze wiki documents.