Direct buffer assign fails

[Andrey Zamaraev]

When assigning integer directly to buffer as:

def emit(self):
    self.buffers[i].state = 0

we got following error:

AttributeError: 'int' object has no attribute 'code'

We have to cast any assigning value to DeferredExpression automatically.

[Andrey Zamaraev]

Direct buffer assignments now works as expected.