Merge pull request #17 from iancmyers/after-fetch

Created afterFetch hook
Added ability to use #get with a query object

The #get model method now accepts an id or a query object. This
addresses the use-case where an error is desired when a row is not
found, but the query is on a column other than id.
Fixed documentation typo around skip/offset.
Added documentation for the afterFetch hook.
Merge branch 'get-query' into sqlbox-mysql

* get-query:
  Added documentation for the afterFetch hook.
  Fixed documentation typo around skip/offset.
  Added ability to use #get with a query object