Non-standard `patternQuality` used instead of `imageSmoothingQuality`

## Issue or Feature
`imageSmoothingQuality` is a [standard feature](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/imageSmoothingQuality) with values `'low'|'medium'|'high'`. In `drawImage()`, node-canvas currently uses its non-standard `patternQuality` prop, which has values `'fast'|'good'|'best'|'nearest'|'bilinear'`:

https://github.com/Automattic/node-canvas/blob/b3e7df319c045c1dc74e390f4b3af161304c9c55/src/CanvasRenderingContext2d.cc#L1376

`patternQuality` is used elsewhere also, so it can't just be renamed and re-valued.

## Your Environment
* Version of node-canvas (output of `npm list canvas` or `yarn list canvas`): 2.10.1
* Environment (e.g. node 4.2.0 on Mac OS X 10.8): all

Relates to #2067