Correcting an issue with buildSchema.

If the attribute is passed as a string, recreate it as an object
and process it normally.
Updating the tests to use waterline-sequel.

The tests now use waterline-sequel generated queries. There are a
few tests that still fail, but all save one are now updated to
use the current build query building mechanism. The adapter.joins
tests were not included in this commit and are still building with
the old mechanism.
Adding appropriate sql options to each Sequel initialization.
Correcting the final set of unit tests.

This commit addresses the final 6 failing unit tests for sails-postgresql.
The changes are only to the tests, and represent changes to the expected
results instead of corrections of aberrant behavior.

groupBy tests:
These tests were corrected by adding an aggregation (avg, in this case)
to the input. The matching output query now matches
```
SELECT "test"."name",
       CAST( AVG("test"."age") AS float) AS age
FROM "test" AS "test"
WHERE LOWER("test"."name") = $1
GROUP BY "test"."name"
```

skip tests:
The LIMIT 184467440737095516 clause was added to support MySQL syntax,
but it doesn't seem to cause problems for Postgres, so I added the
limit clause to the expected output. If this isn't satisfactory, we
could make the LIMIT clause inclusion based on a new SqlOption value.

where tests:
Corrected spacing in the output query. The actual fix for these tests
were in balderdashy/waterline-sequel#18.

join tests:
I don't love the solution to this one. The query was changed from:
```
SELECT
	user.name,
	user.id,
	user.createdAt,
	user.updatedAt,
	pets_pet.name AS pets_pet__name,
	pets_pet.id AS pets_pet__id,
	pets_pet.createdAt AS pets_pet__createdAt,
	pets_pet.updatedAt AS pets_pet__updatedAt,
 	pets_pet.owner AS pets_pet__owner
FROM user
LEFT JOIN pet AS pets_pet
ON user.id = pets_pet.owner
WHERE user.id IN (
			SELECT user.id
			FROM user
			LIMIT 30
			OFFSET 0)
```
to
```
SELECT
	user.name,
	user.id,
	user.createdAt,
	user.updatedAt,
	__pet.name AS id___name,
	__pet.id AS id___id,
	__pet.createdAt AS id___createdAt,
	__pet.updatedAt AS id___updatedAt,
	__pet.owner_id AS id___owner_id
FROM user AS user
LEFT OUTER JOIN pet AS __pet
ON user.id = __pet.owner
LIMIT 30 OFFSET 0
```
these are functionally the same, but the inputs needed to change drastically
to generate them.
Merge pull request #124 from DavidEBest/unit-tests

Updating unit tests to use waterline-sequel generated queries.