Execute a remove expression.  Should generally only be called implicitly.

def execute_remove(self, remove):
		''' Execute a remove expression.  Should generally only be called implicitly.
		'''

		safe = self.safe
		if remove.safe is not None:
			safe = remove.safe

		self.queue.append(RemoveOp(self.transaction_id, self, remove.type, safe, remove))
		if self.autoflush:
			return self.flush()