Merge pull request #3289 from hjdivad/fix-3273-guid-as-tiebreaker

`Ember.computed.sort` fallback to guids.
`ReduceComputed` groups changed properties.

This is mostly important for sorting when items are changed via `setProperties`
instead of a sequence of `set`s.
fix nested yield
Merge pull request #3290 from hjdivad/array-computed-sort-via-sortProperties

`ReduceComputed` groups changed properties.
Typos and whitespace
IE indexOf fix again, this time without breaking every other browser
Merge pull request #3291 from lukemelia/ie-index-of-fix-moar-compat

IE indexOf fix again, this time without breaking every other browser
Version bump - v1.0.0
Fix ember-source to handle non-RCs
Fix size calculations on website
Contribution section added to README.md
reference CONTRIBUTING.md
Merge pull request #3292 from ysksn/master

Contribution section added to README.md
fixed duplicated @param
Merge pull request #3298 from makepanic/patch-1

fixed duplicated @param
update ember-source
Fix typo in docstring
Reuse variable
fixup docs (mostly formatting)

(@stefanpenner / @rjackson)
Merge pull request #3304 from sebastianseilund/simplification1

Reuse variable