Erroneous mention of "with block"

[keithellis74]

In the Push Button Stop Motion resource, the section titled 'Take a picture with python',

https://github.com/raspberrypilearning/push-button-stop-motion/blob/master/worksheet.md#take-a-picture-with-python

In step 7, the line " inside the with block, so it becomes:"

The code shown does not have a with block. reference to this should probably be removed.

[bennuttall]

Thanks