Merge pull request #192 from benzittlau/add-remaining-delete-methods

Adds delete methods for remaining supported services.
Merge pull request #191 from benzittlau/remove-unused-delete-options

Removes unused options from service delete methods.
Merge pull request #190 from benzittlau/add-delete-for-purchases

Add ability to delete purchases.
Merge pull request #189 from benzittlau/add-line-helpers-to-purchase

Adding line detail helpers to the purchase line item.
Merge pull request #188 from benzittlau/add-helpers-to-qb-line

Add helpers for other line details to line model.