Add promise then to custom emitter
Run tests for 0.10 as well
PG does not like v0.10. Update buster dep. to 0.6.3
add test for skipping validations when value is null and allowNull is true
Merge pull request #634 from tremby/allowNull-skip-validations-test

add test for skipping validations when value is null and allowNull is true
Merge pull request #626 from kevinbeaty/emitpromise

Promises/A Support
promises/a support
Enable the override of the default attributes