SQLDB.js updates:
- Modified sort order for processed trip results, and updated affected SQL
  create table/select/update statements where relevant;
- Added getClientCode(), deleteClientCode() and deleteTrip() functions;
- Separated processTrip() into individual logTrip() and processTrip()
  functions;
- Added conditionals for callbacks;
- Updated/added Javadoc comments
Merge branch 'master' of https://github.com/KatieBarnett/PCM-ExpenseApp