renamed "mod"-related fields to "custom" because I kept getting confused.
renamed "mod"-related fields to "custom" because I kept getting confused.

	* src/orca/script.py: renamed "mod"-related fields to "custom"
	because I kept getting confused.

pvagner/orca,chrys87/orca-beep,h4ck3rm1k3/orca-sonar,chrys87/orca-beep,GNOME/orca,pvagner/orca,pvagner/orca,pvagner/orca,GNOME/orca,h4ck3rm1k3/orca-sonar,GNOME/orca,h4ck3rm1k3/orca-sonar,chrys87/orca-beep,chrys87/orca-beep,GNOME/orca