They seem to have disappeared between 0.7.2 and 0.7.3, although there is no mention of it in the changelogs. I also see a couple new Actions, AccelAmplitude and AccelDeccelAmplitude, although if I simply substitute them in and change rate to duration they do not work. I get this exception:
[NSException raise:@"IntervalAction (Amplitude)" format:@"Abstract class needs implementation"
Here is the diff where Accel and AccelDecel were removed: