update browserfiles and commit `set` tests
Merge pull request #239 from garygreen/feature/customize-globals

Added ability to add/customize globals with: addGlobal(name, func)
Merge branch 'master' into oddbird

* master:
  update browserfiles and commit `set` tests

Conflicts:
	browser/nunjucks-slim.min.js
	browser/nunjucks.js
	browser/nunjucks.min.js