Localizing JS for kit-making to a single view

Removing the spree_product_assembly JS from the global manifest
Guarding against breakage for projects with existing dep
Updating Gemfile + gemspec definition
Removing all unneeded files
throws MethodError order_id_equals doesn't exist, replace with where(:order_id => order.id)
Code cleanup
All tests are passing
Merge pull request #20 from iloveitaly/cleanup

All Tests Passing + Misc Cleanup
Allow any Spree 2.0.0 version
Allow beta Spree 2.0.0
Append routes to core so that normal product search routes can be found

Fixes #25
Tell Gemfile where to find Spree 2.0.0
Require correct testing_support/common_rake file
Fixing Spree::Product.active to reflect the change in parameters in spree core

Fixes #28
Require Spree 2.1.0.beta
Remove references to methods removed in spree/spree

So that we can actually boot the app
Spree::Variant no longer has a `on_hand` attribute

Instead stock it should be check through variant stock items. This makes
it possible to go through checkout without raising errors
Allow test to run

Update factory girls and test helpers path
Remove specs that give no value to the extension

They were basically testing spree core functionalty. No need to maintain
those here
Hook parts into new Spree stock API

So that they are included on shipments and have their inventory units
changed as expected. Most of the previous code was completely removed
since it didn't make sense anymore