- Migration to typecast "0" and "1" valued is_k1 properties to boolean
- Make checkboxes store properties as boolean values using helpers in the view & controller
Add destringify boolean helper tests
Merge branch 'finished' into destringify_booleans

Conflicts:
	db/schema.rb
Merge remote-tracking branch 'remotes/origin/finished' into destringify_booleans
- Add blockly "true" and 'false" string-to-boolean conversion
- Add tests for blockly string coercion conversions
- Remove coercion-in-controller code
- Adjust migration timestamp to force schema run
- Change is_k1 to isK1
Test coercion of negative numbers
Merge pull request #882 from code-dot-org/destringify_booleans

Add skip instructions checkbox, fix checkboxes