Add standard knex functions

doSelect, doInsert, doUpdate, doDelete

fixed bug

Various fixes based on feedback

 - moved require to top of screen
 - simplified doSelect function
 - updated doInsert to return the entire object
 - removed debugging logging

Additional updates as a result of review

- returning back a single object, instead of an array, for doInsert
- returning null resultset if error and returning raw number of records
affected if success for doUpdate, doDelete
- Added endline at end of file
Update existing models to use knex
Add travis build config file
Merge branch 'master' into ag-workout

Conflicts:
	tests/workoutSpec.js