kernel: Fix IndexOutOfRange with empty matches in the regexp

It is possible to have a non nil Interval that is empty. Make
the code work on isNil or isEmpty to avoid the exception.

Fixes:
SystemExceptions.IndexOutOfRange(Exception)>>signal (ExcHandling.st:254)
SystemExceptions.IndexOutOfRange class>>signalOn:withIndex: (SysExcept.st:660)
Interval>>first (Interval.st:245)
Kernel.MatchingRegexResults>>at: (Regex.st:382)

2013-12-08  Holger Hans Peter Freyther  <holger@freyther.de>

	* kernel/Regex.st: Check for isEmpty of the Interval before
	trying to use it.

2013-12-08  Holger Hans Peter Freyther <holger@freyther.de>

	* kernel/RegexpTests.st: Add tests for Regexp.
libgst: Create a BindingDictionary for the VMPrimitivies

Make Behavior>>#allSharedPools not end in a DNU.

2013-12-16  Lee Duhem  <lee.duhem@gmail.com>

	* dict.c: Make VMPrimitives a BindingDictionary.
kernel-tests: Check that Behavior>>#allSharedPools does not DNU

Make sure that the method at least does not generate a
DoesNotUnderstand exception.

2013-12-16  Holger Hans Peter Freyther  <holger@moiji-mobile.com>

	* kernel/BehaviorTests.st: Add tests for Behavior.
Merge branch 'master' into myself