New additions for Expose, Specific Daykill evasion, and Polkabot fix for Daykills

Specific breakdown:

-Daykills get "ignore" allowing stuff like Soren to evade Ike's daykill

-Polkabot now gets properly warned when someone revenges a daykill with a message defined

-Expose gets a bunch of new stuff, everything is identical to Daykill unless noted:
--Evade
--EvadeChance
--Ignore
--RevealChance
--Reveal Exposer (Reveals exposer when exposed)
--Revenge (Exposed role will kill the Exposer)
--Related messages such as exposemissmsg and evasionmsg to mirror what Daykills have
Merge pull request #353 from Fuzzysqurl/master

New additions for Expose, Specific Daykill evasion, and Polkabot fix for Daykills