Feature/rails3

Migrated acts_as_silent_list to rails3 (actually already rails4)
- Created empty scaffold using scaffold generator
- Manually merged latest acts_as_silent_list version into scaffold according to new structure
- Created new git repository for this, so applying changes to github needed complete delete
 of latest former version
- Adopted current initialization code from acts_as_list
- Fixed test failures and warnings for rails versions 3.2.13 and 4.0.0beta1