CSM Spined Beast

Added Spined Chaos Beast to elites as per IA 13
CSM Giant Spawn

Removed Giant Spawn as per IA 13 (No longer a Chaos Marines option)
CSM Plague Zombies

Enabled show of plague zombies by selection of Necrosious as per plague
zombies rule IA Apoc 13
Merge remote-tracking branch 'upstream/master'
Merge pull request #469 from HoboDaveGoBOOM/master

CSM Unit entires from IA 13