Update adding-child-routes.md

It wasn't clear that a new empty function() needs to be added to resource() in order for child routes to work at all. This commit briefly explains that this empty functions is necessary
change to standard jquery ajax call

jQuery.ajax expects (url, settings) as parameters.  The ajax call to /error-notification used (url, type, settings), which generates a 'GET' in latest version of Chrome, even if 'PUT' is given as the second parameter.
Clarification about setters
Remove EmberConf callout.

As requested by @wifelette, since EmberConf is current sold out do not
display the logo/link on the homepage.
Fixed typos
Added adding-google-analytics-tracking to the index
Merge pull request #1292 from emberjs-cn/patch

Patch
Add 1.4.0 blog post.
Added unlockable.com
Add note to registerHelper section

Helpers must be registered before injecting the test helpers.
Merge pull request #1295 from kategengler/patch-1

Add note to registerHelper section
Merge pull request #1294 from shamoons/master

Added unlockable.com
Merge pull request #1263 from abremod/master

change to standard jquery ajax call
make indentation on debugging page more consistent
Merge branch 'patch-1' of https://github.com/soundasleep/website into soundasleep-patch-1

Conflicts:
	source/guides/getting-started/adding-child-routes.md
Merge pull request #1273 from H1D/patch-1

Clarification about setters
Touch up a sentence on getter/setters for CPs
Update rendering-a-template.md
Add 1.4.0 to home page.
Show 1.4.0 on builds site.