FIX DURATION BUG

avoid negative durationLeft
Merge branch 'DurationView-BUG#27'
Merge branch 'DurationView-BUG#27' into Running-on-Device

Conflicts:

MDTomatoClock/MDTomatoClock.xcodeproj/project.xcworkspace/xcshareddata/M
DTomatoClock.xccheckout

MDTomatoClock/MDTomatoClock.xcodeproj/project.xcworkspace/xcuserdata/Dev
eloper.xcuserdatad/UserInterfaceState.xcuserstate
	MDTomatoClock/MDTomatoClock/MDDurationView.m
Merge branch 'Running-on-Device'

Conflicts:
	MDTomatoClock/MDTomatoClock/MDDurationView.m
Revert a7a0214..5786e5b

This rolls back to commit a7a0214a0d729bd97e97f6928803c448fdd68a0d.
Merge branch 'DurationView-BUG#27' into Running-on-Device

Conflicts:

MDTomatoClock/MDTomatoClock.xcodeproj/project.xcworkspace/xcshareddata/M
DTomatoClock.xccheckout

MDTomatoClock/MDTomatoClock.xcodeproj/project.xcworkspace/xcuserdata/Dev
eloper.xcuserdatad/UserInterfaceState.xcuserstate
MDTomatoClock/MDTomatoClock/MDDurationView.m