Fix package.json main module

This fixes the path to the main file in package.json from dist/cjs/can-assign.js to can-assign and remove the main from steal config.

Fixes #19

QUNIT2 upgrade

This updates the tests to use QUnit@2.x.x.

#18

v1.3.1

• Removed "use strict" from .js files #10

v1.3.0

• Added 'use strict' #7

v1.2.0

Add assign to can-namespace #8

Updated docs and added cycle detection

• Add a cycle detection script to test process #2
• Update docs with new @parent & @collection #4

v1.0.0...v1.0.1