implemented (Inner)ActorCat1Group

[cdwensley]

This fixes issue £144.
Implementations just convert to xmod, construct actor, convert back again.
Also dealt with one or two queries in the library, marked #?

[codecov]

Codecov Report

Attention: Patch coverage is 92.30769% with 1 line in your changes missing coverage. Please review.

Project coverage is 78.82%. Comparing base (2c22a50) to head (7d8ca86).
Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
lib/gp2ind.gi	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #148      +/-   ##
==========================================
+ Coverage   78.75%   78.82%   +0.07%     
==========================================
  Files          41       41              
  Lines       14189    14194       +5     
==========================================
+ Hits        11174    11189      +15     
+ Misses       3015     3005      -10     

Files with missing lines	Coverage Δ
lib/apps.gi	47.94% <ø> (-0.01%)	⬇️
lib/gp2act.gd	100.00% <100.00%> (ø)
lib/gp2act.gi	93.50% <100.00%> (+1.69%)	⬆️
lib/gp2ind.gi	67.89% <85.71%> (+0.02%)	⬆️