Staking bug updates

[mbeylin]

Implements fixes for:

63 , #64 , #66, #69, #74, #75 , #76, #77, #78, #79 , #80 , #81 , #82 , #84 , #85 , #86, #88 , #89, #90, #91 , #92 , #94, #96

[skmgoldin]

Will review next week. 👍🏻

[skmgoldin]

@akuanti and I reviewed this! Overall it looks good. We did not review the tests.

Concrete suggestions:

• Rename Whitelist struct to ClaimantTerms
• Rename the whitelists array to whitelistedClaimants
• Change isBeforeDeadline to use < rather than <=, otherwise the check is not strictly "before"
• The @param _minimumFee definition for the whitelistClaimant function contains a typo.
• Checking that the claimant is not the staker or the arbiter in the whitelistClaimant function seems a bit hopeless, as either party could simply sybil.
• Stale comment in getNumWhitelists function. Should refer to the whitelists array, not the claims array.
• Change getNumSettlements to getNumSettlementProposals and update the comments accordingly as well.

General notes:

• Use SafeMath everywhere.
• Don't forget to run the linter on your tests!!!!!
• We should consider inheriting a shared enum for different ruling types that both DS and DV should use.
• In light of:

  Checking that the claimant is not the staker or the arbiter in the whitelistClaimant function seems a bit hopeless, as either party could simply sybil.

do we need to consider other solutions to the problem of stakers whitelisting themselves?