Improve ent validity checking in CalcElasticConsts (#1261)
Improve ent validity checking in CalcElasticConsts (#1261)

Fixes #1258.
thegrb93/wire,Grocel/wire,garrysmodlua/wire,bigdogmat/wire,sammyt291/wire,wiremod/wire,dvdvideo1234/wire,NezzKryptic/Wire