Only drop table if exists
Merge pull request #1 in ORNO/db from develop to master

* commit 'dd4629e333e2747f8c9b2e792e41e848d0a874d0':
  Only drop table if exists
Add check for driver based on dsn
Check if ['database'] is set as this is optional
Merge pull request #3 from lgoldstien/GenericDriverCheck

Add check for driver based on dsn