Support ilike for Postgres

Waterline version:0.13.4 Node version:8.9 NPM version:5.0 Operating system:All

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waterline/utils/query/private/normalize-constraint.js should support ILIKE. This would be a super simple change the the existing 'like' condition.

A simple update to:

else if (modifierKind === 'like' || modifierKind === 'ilike') {