Prevent memory leaks and improve performance

[PaulWoitaschek]

• In case someone passes an activity, we need to make sure we are using the application context.
• In case there is no downscaleFactor set, we don't need to apply a matrix to the canvas

[austinkettner]

@PaulWoitaschek Thanks for submitting this! We are debating how to handle PRs going forward, for example we are thinking about potentially requiring CLAs to be signed.

Will get this wrapped in the next day or two and your changes merged in!

[emersoncloud]

Hey Paul I wanted to follow up on what Austin mentioned earlier. We are not sure of our future plans for the BlurKit project quite yet. To avoid the need for licensing agreements we aren’t going to merge your changes directly. We have resolved your concerns in our latest PR #45. We really appreciate your contributions as it did help contribute to our PR, so definitely PR going forward as it’s a great way to get changes integrated directly =)