dual wielding animations missing layers/components

[collinsmith]

Selecting LH components list for RH only animation results in a null layer. Temp fix referenced below checks for null layer and ignores.

Some layers are missing -- e.g., left hand swing does not contain any weapons in the right hand (appears to be HTH only is added for RH).

I think both of these issues are related and additional logic might be required for adding the missing layers for dual wielding cases (see assassin dual wield claws also). See 3b9311b