use Model.all instead of Model.scoped

Fixes #56
use update_column
use where.not
use activerecord >= 4.0.0.beta1
access where_values_hash via string
Model.exists? returns truthy or falsy
Merge pull request #61 from delba/rails4-upstream

Use update_column and where.not
bump AR dependency to ~> 4.0
Bump to 2.0.0 (for Rails 4)
Update README with rails4 instructions
Add Model.restore(ids) function

Modelled on AR::Relation.destroy
Merge pull request #69 from fullcirclegroup/class-level-restore

Add Model#restore(id)
destroy! when destroying deleted? records
Add test for destroy of a deleted? object
Add description of destroy! behavior to README
Remove call to update_column deleted_at that was 'deleting' things before their time
Fix double destroy test
Add callbacks for 'new' AR lifecycle :restore

Fixes #72
Use quoted table name in default scope (call me paranoid)
Update rails4 branch name in README