Feature request - Add ability to run a single group and make it repeatable

[abid-mujtaba]

Full disclosure, I tried to make this work by creating a dummy group:

define_group _:
    animate_100 pause

and then used run_groups_together <some-group> _ which works out fairly well and allows me to use define_group for grouping commands together even when I do not want to run multiple groups in parallel.

It would be nice to have a different command, for example, run_group <single-group>, which does the same thing so I can avoid this hack.

Additionally, it would be nice to have the ability to be able to run the same group multiple times, I have some sub-loops that I want to run 2 or 3 times (interleaved with other stuff). This does not seem to be currently possible. Repeated invocations of run_groups_together seem to be ignored.