Amend CONTRIBUTING:

* Mention about ticket references in commit message
* Add extra rules for Ruby 1.9 hash syntax and lambda syntax

[ci skip]
Clean up README [ci skip]
Update README to point to WIKI page for Core Team [ci skip]
Improve transferring stock between two stock locations
- Refactor controller method and move the work to the stock location
  model
- Don't allow a transfer to occur if the source location doesn't have
  enough inventory
only show eligible adjustments on the backend
Add spec coverage to shipping a completed order
fix up default stock location
update adjustment states for migrating stores
add shipping_rates to existing shipments
use proper up/down to restore the shipping_method_id on shipments