Bitwise operations should have unsigned type

[guillep]

Otherwise, conditionals depending on them will use signed jumps instead of unsigned jumps.
For example, the next piece of code, should be translated using a jumpAbove and not a jumpGreater.

	r := (self stackTop bitAnd: 16rFFFFFFFFFFFFFFFF) > 1
		     ifTrue: [ 1 ]
		     ifFalse: [ 2 ].
	self pop: 1 thenPush: r

[guillep]

This affects bitAnd, bitOr, etc