Bug 89020 [Undo] Operation throws assertion failure if undo limit is set to 0
I20050324-0800 Unfortunately existing clients of text's undo manager were allowed to set any number without failing. This is no longer possible: an assertion failure occurrs if the limit is smaller than 1. I will add code on my side that will handle the negative numbers but the operation history must allow 0.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/DefaultOperationHistory.java
} else {
			index = redoList.indexOf(operation);
			if (index == -1) return;
			ArrayList allContexts = new ArrayList(replacements.length);
			redoList.remove(operation);
			internalRemove(operation);
			for (int i=0; i<replacements.length; i++) {
				IUndoContext [] opContexts = replacements[i].getContexts();
				for (int j=0; j < opContexts.length; j++ ) {
					allContexts.add(opContexts[j]);
				}	
				redoList.add(index, replacements[i]);
				notifyAdd(replacements[i]);
			}
			
			for (int i=0; i<allContexts.size(); i++) {
				IUndoContext context = (IUndoContext)allContexts.get(i);
				forceRedoLimit(context, getLimit(context));
			}
	
		}
		
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IOperationHistory#setLimit(org.eclipse.core.commands.operations.IUndoContext, int)
	 */
	public void setLimit(IUndoContext context, int limit) {
		Assert.isTrue(limit > 0);