* Remove unused variables
* Simplify cached elements, IDs are unique
* Use chaining for event binding
* Use IDs directly, no benefit in caching
* DRY out the update logic
* Remove cacheElements since it's now named wrong

Update to polymer 1.2.3

Humble: Don't create new todos with empty titles. Fixes #1516.

This reverts commit 54107834.

This reverts commit 6cce0138.

closes #1507

[backbone_marionette] move backbone.history.start() after controller initialization

Update TroopJS to latest 3.0.x and new template.

xrefs #1491 #1218 #1215

Add a new framework: GopherJS + Humble

angularjs: simplify clearCompleted method

* Remove unused `completeTodos` variable
* use `Array#filter` instead of `Array#forEach`

correct actual vs. expected order in assertions

See https://nodejs.org/api/assert.html. The "actual" value should come
first, and the expected value should come second. This ordering is
important in order for the output describing a failed test to be
correct/accurate.

Angular: add missing semicolons

Fix typo "reduntant" to "redundant".

docs: Adjust minor grammar and punctuation issues

Close #1457