Fee calculations

 - Add ClaimFeeCalculator to calculate hearing and application fees
   for jurisdiction 1
 - Add Claim#claimant_count because Law of Demeter
 - Move some specs from models directory into new services directory
Fee calculations:

 - Calculates fees for claim type 2, i.e. non-discrimination and
   non-unfair-dissmissal claims
 - Adds Claim#alleges_discrimination_or_unfair_dismissal? which
   delgates through to ClaimDetail#alleges_discrimination_or_unfair_dismissal?
 - Adds ClaimDetail#alleges_discrimination_or_unfair_dismissal?
Fee remissions

- Add remissions calculations to ClaimFeeCalculator
- Add remissions to form

Closes #25
WAT

A migration somehow went missing. I don't even...

💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩💩
Merge pull request #26 from ministryofjustice/fee-calculation

Fee calculations