Added ability for units list in Snippets Editor to persist units in list and reload them when next display.
Settings object extended with new UnitList storage to facilitate this.
Implements feature request #3560962 (http://bit.ly/UM0c0B)
Authored by: delphidabbler 2012-12-19
Parent: [r2610]
Child: [r2612]
