Add first-class Array support to Postgres dialect.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	lib/dialect/postgres.js
	lib/node/valueExpression.js
Add array tests, for both literals and array columns.
Add HSTORE as top-level Postgres function.
Add hstore tests for literals, concatenations, and key access.
Add tests for array concatenation.
Merge pull request #145 from matinm/array-hstore

Add array and Hstore as first-class objects.