E2 Bodygroup Functions

The functions are a bit redundant as the e: functions will work on holograms, but I made both for the sake of consistency, and you don't always want to return the entity of a hologram. If you want to test these out quickly, use a tf2 ragdoll or a hl2 jeep/airboat.

```
e:setBodygroup(GroupID, GroupSubID)
N = e:getBodygroups(GroupID)
holoBodygroup(Index, GroupID, GroupSubID)
N = holoBodygroups(Index, GroupID)
```

Keep in mind that models with bodygroups (because bodygroups use bones) do not scale properly with holoScale. Someone said they could add holoBoneScale? Might be a good idea.

Also added the following default hologram models:
```
"cplane" // a circular plane
"rcube" // low poly versions of the hq_rcube models
"rcube_thin"
"rcube_thick"
```

And I fixed the smoothing groups on the _"right_prism"_ model.