misc...
* restrict unwanted angle(s) keys commits on moving generic, eclassmodel, miscmodel entities
* reverted angle(s), origin, scale entity keys save format from %f to %g
* fix uniform rotation operations for generic entities with angles key
* use more precise meth for rotating point entities with only angle rotated
* snap tiny inaccuracies in angle(s) and origin point entities keys
* workaround: don't discard empty group ents, having origin key
* entity class convertion: prevent converting worldspawn; prevent converting point entity to empty group
