Initial work on ES6 modules
More modularization
Building an AMD file
Further progress towards modularization.

At this point, I have only 2 fails in the Node build, but I'm doing a
bunch of manual stuff locally and still have a bunch of hacks.
Make the Handlebars environment into an object

The idea is that the environment wraps up the mutable stuff in
Handlebars (like the helpers) and that you could theoretically create a
new one at any time and pass it in to Handlebars.template.

Every test makes a new environment and uses it in template compilation.
Move more testing mutations into the environment
Global Handlebars.compile uses its env

The basic strategy is that there will be a global Handlebars object for
the browser build, and that object will have a `compile` on it which
uses its environment in the compiler.

It will also be possible to glue things together manually by using the
AMD build and passing the environment to `compile` directly. Some of
these details are TBD.
Move dist dir generation into Grunt
Add jshint to grunt exec
Move test runner into grunt
Move parser generation into grunt file
Add Swag to the "Handlebars in the Wild" list.
Merge branch 'master' into grunt-build
Version update task
Add grunt bench command
Fix benchmark dependencies
Fix fastest test lookup
Handle edge case in benchmark layouts
Differentiate between failures and skipped tests
Better skipped test handling