Fix import in readme

[onskateboard]

import Mock.GPIO as GPIO (like in the example)

[Aananth K]

@onskateboard thanks for creating the issue, can you be specific..?

[onskateboard]

in your docu you suggest after installing:
To use the emulator just type the following at the beginning of your script.

from Mock.GPIO import GPIO

but you can import only: from Mock Import GPIO
or you can import it like in your examples import Mock.GPIO as GPIO

[Aananth K]

Thanks @onskateboard, resolved this issue now.

looking forward to seeing more suggestions.