Refactored tests for limit and offset.
Added limit() and offset() with aliases.
Merge pull request #2083 from daylerees/skip-take-aliases

Added limit() and offset() to Query Builder.
Fixed inverse logic error

Updating the model when it already exists and create a new one if it doesn't.
Merge pull request #2100 from peaceman/4.0

Inverse logic error in the model update method
Reverting change.