Fix for convert throwing ArithmeticException
RESOLVED - bug 432200: MassAmount unit conversion seems to have multiply
and divide reversed 
https://bugs.eclipse.org/bugs/show_bug.cgi?id=432200
Merge remote-tracking branch 'upstream/master'

Conflicts:
	bundles/org.eclipse.uomo.ucum/src/main/java/org/eclipse/uomo/ucum/impl/UcumEssenceService.java