Alter SQL and improve checks in Estimate->listEstimates() method
Check if any estimates are returned from the DB and print warning to screen if none are found
Update SQL in Invoice->listInvoices() method
Merge branch 'master' of github.com:MasterRoot24/alpha-crm
Merge branch 'master' into develop

Conflicts:
	app/classes/Estimate.class.php
	app/classes/Invoice.class.php