Changed record_restored-attribute from boolean to integer.
record_restored column now contains the version number from the version record, from which the original record was restored, or nil, if the record was not restored.
Added methods  "record_restored" (returns boolean) and "record_restored_from_version (returns integer or nil) for comfort.
Renamed "record_restored_flag" to "record_restored_column".
:dependent => :nullify can not be used any longer in version-association (acts_as_versioned raises an exception, if this option is used).
Removed option :dependent => :nullify from test class Widget.
Merge branch 't7878_version_every_change' into rails3