New 3.9a at

http://ftp.squeak.org/3.9alpha/Squeak3.9a-6721.zip

ChangeLog:
----------------

	- Tools for traits fixes from adrian
	- underscore fixing
	- integer printing fixes + tests
	- 0002708: SharedQueue does not nil out unused slots when flushing
	- 0002154: Light-weight mutex implementation
	- tests from 0002688: aNumber = (aNumber + 0 i) answer false
	- Adds a test for the new Url class>>absoluteFromFileNameOrUrlString:
	- Set new now uses new: 5
	- delete Undefined>>languagePrefs, broken code
	- tests for primesUpTo: and isPrime
	- turn on Deprecation warnings
	- Move Heap examples to HeapTest (and call them in a test)
	- remove double entry for TestRunner from open Menu
	- clean a bit old unneded tests
	- remove empty class and method categories
	- fix a call to deprecated #bringFlapTabsToFront
	- Change Set:		fixPntrFinder-bf
	  Author:			Bert Freudenberg
	  The PointerFinder (aka 'chase pointers' menu item) did not find  
references in
	  CompiledMethods, which are the only objects in the system that  
answer false to isPointers
	  but still *do* have pointers

    Marcus