Messages and controls widgets refresh every 10ms (same as module widgets).
Fixed error when trying to remove a message when no message is selected.
Made messages widget extendable. Fixed accessing transform buffer by time.
Fixes #7, messages can be selected. The selected message is reselected after the widget is refreshed.
Fixes #7, scrolling is no longer reset to view the selected message after every widget refresh.
Fixes #8, message time stamps are displayed relative to the time stamp of the first transform in its buffer (or the first message if no transforms exist). Note that this only affects the display, not the way time stamps are stored inside the data structure.
Standardizing PerkTutor widget behaviour.
Merge branch 'master' of https://github.com/PerkTutor/TransformRecorder into PerkTutor-master

Conflicts:
	Widgets/qSlicerMessagesWidget.cxx
Merge pull request #2 from mholden8/PerkTutor-master

Perk tutor master