Add state aid threshold amount to SIC codes.

Certain sectors have a lower state aid threshold,
the default is 200,000 euro.
Show correct SIC state aid threshold when updating lending limit
State aid must not exceed SIC threshold at Loan Entry
Utilise the #sic association.
Merge pull request #225 from alphagov/sic-state-aid-thresholds

SIC state aid thresholds
Check loan is still valid when updating lending limit.

Update state to Incomplete and redirect to loan entry if not.
EFG not SFLG
Remove 'overdraft' from question text
Update question text
Update question text
New question text
Merge pull request #226 from alphagov/phase-6-update-lending-limit

Ensure that the loan is still valid when changing its lending limit
It's much easier to switch branches if we can revert database changes.
Minor tweak

That sentence needs removing and rewriting completely.
Merge pull request #228 from alphagov/misc-text-changes

Misc text changes
Claim Limit calculators for Phase 1 - 6
Add claim limits to lender dashboard
New layout for dashboard, with peity pie charts!
Use inheritance for phase rules.

Each new phase rules object defines what has changed
from the previous phase.
Return correct phase rules object in Loan#rules