* Makes network eslint compliant
Unused variables in private functions, who were never called internally with those arguments were removed.
lint rule was disabled for public functions, and in private functions which were called internally with those unused arguments

* Disables linting for unused args passed into DataSet and DataView

* Set dimensions properly of images on initialization.

Fix for #3203

Image nodes were assigned the default size on initialization, leading to very compressed images.
This fix adjusts the default size as soon as the images used have been loaded.

The approach for dealing with this has been adapted from `CircularImage`.

* Fixed tabs

* Consolidate code for determining the pixel ratio

* - Removed local param  'pixerRatio' from CanvasRenderer. Now only canvas.pixelRatio is used.
- consolidated ctx.transform() calls in Canvas
- Added/edited commenting (also TODO's)
- Added Canvas.getContext()

* CachedImage with preredendered zoom images; first working version.

* Fixes for missing images and usage brokenImage.

* Remove unused method

* Added height member of CachedImage, note about svg's