Adds setting instance.breakSaveOnErrors (default: true)

When set to false, using .save() will not return on first error.
Instead it will collect all validations and then return an Array of
errors.
Changes error variable names to avoid confusion
Changes setting name from instance.breakSaveOnErrors to instance. returnAllErrors (#96)
Adds type: "validation" to instance.save() validation errors
Changes test to check for `type: "validation"` on validation errors
Merge pull request #101 from dresende/validation-all-errors

Validation all errors
Adds `groupBy` to aggregate functions
Fixes column names when using groupBy (and returns all rows)
Updates sql-query dependency to 0.0.16 (#99)
Adds groupBy to aggregate methods (#99)
Updates sql-query dependency to 0.0.17 (fixes previous version not supporting correctly postgresql) (#99)
Updates test-aggregate-groupby to be row order independent
Removes index on postgresql primary keys
Fixes property defaultValue not being set if property is null (closes #104)

Added a test for this and fixed another one.
Fixes bug detected on previous commit about drivers using wrong escape methods (#104)
2.0.8

#97, #98, #99, #104, ..
Correct 'returnAllErrors' setting behaviour
Merge pull request #107 from locomote/return_all_errors

Correct 'returnAllErrors' setting behaviour