clear and undo buttons

[Niyatizzz]

fixes issue #14
building up on pr #15
clear button clears everything on the screen while the undo button clears only the drawing leaving the dots as required
do let me know if it requires further changes

[quozl]

Thanks. There was too much change. Please don't make changes to whitespace and don't commit your own files like settings.json.

https://github.com/sugarlabs/sugar-docs/blob/master/src/contributing.md#making-commits is our suggestions on commit messages.

How did you test the activity? Activities must be tested inside Sugar.

[Niyatizzz]

I have cleared the extra whitespaces and have tested the activity on sugar as well

[quozl]

How did you test the activity?

Still the same amount of whitespace change, see https://github.com/sugarlabs/connect-the-dots-activity/pull/18/files for most of index.html and activity.js.

@chimosky please also review?

[chimosky]

I agree with Quozl, there's just a lot of change to the syntax which makes your actual change difficult to review.

You should also take a look at our contributing guide, we usually don't open PRs from the master branch.