(skip revision) Remove old conversation system
Conversations model
Simple nodes: effects, lines, wait
Fork nodes: options nodes, conditioned node
Trigger conversation effect
Conversation processor and component
Minor refactors
Trigger conversation executor
Simple runtime nodes
Fork runtime nodes
Added test for conversations
Move and split DemoBuilder to engine
Provisional systems to render lines and options in conversations
Demo for conversations
Merge pull request #698 from anserran/convrefactor

New types of nodes and tests for conversations