More JavaScript-ey development system

 * Replace Rake with Make
 * Replace Jasmine with Mocha, Mocha-PhantomJS, Chai
 * Replace Gem & Bundler with npm
Merge pull request #52 from jamesarosen/better_tests

More JavaScript-ey development system
first stab at Travis build [Fixes #51]
update jshint to 2.0.x
add spec: dotted keys win over nested ones [Fixes #48]
refactor lookupKey: use multiple returns
remove outdated "Building" content from README
spec is compatible with Ember 0.9.8.1
add Handlebars to devDependencies
also test against Ember 0.9.8.1 [Resolves #50]
Travis: specify language: node_js
extract eachTranslatedAttribute

The logic of iterating over ___Translation attributes in an object was
inside the TranslateableAttributes#didInsertElement. This extracts it
to a helper that that method calls.
Add TranslateableProperties mixin

The existing TranslateableAttributes mixin takes ___Translation
properties on the view and turns them into attributes on the view's DOM
element.

The TranslateableProperties mixin takes ___Translation properties on any
Em.Object and turns them into attributes on the object itself.
Merge pull request #54 from jamesarosen/translated_properties

Add TranslateableProperties
Bower: relax dependencies [resolves #53]
use new bower.json standard
version 1.4.0
README: s/defaultLocale/defaultLanguage [fixes #57]
README: mention alternate translation hash format [fixes #56]
README: better TranslateableProperties docs

 * Use an existing translation key from the docs
 * use the "yields..." format like all the other examples do