docs: Fix a few typos

[timgates42]

There are small typos in:

• doc/tuning.md
• src/imageserver/imaging_pillow.py
• src/imageserver/static/js/canvas_view.js
• src/tests/junitxml/init.py

Fixes:

• Should read targeting rather than targetting.
• Should read nothing rather than nnothing.
• Should read helper rather than heleper.
• Should read accuracy rather than accurancy.

Semi-automated pull request generated by https://github.com/timgates42/meticulous/blob/master/docs/NOTE.md

[fozcode]

Thanks Tim! Note that unfortunately this project is no longer being actively maintained.

[qururoland]

Hi Tim, Thanks for your contribution to QIS. As Fozcode said, the project is not getting that much attention at the moment mostly because it's reached a stage where it is running fine and the putting in the time needed to make further changes isn't high enough up our priorities. The code is being heavily used in several projects but if you are looking for a solution like this then we'd love to hear what you are using it for.