Fix some inaccuracies in the tutorial.

[UriyaHarpeness]

There's an undocumented difference between docs/examples/tutorial/stopwatch03.css and docs/examples/tutorial/stopwatch04.css, so I've equalized that part, and sorted the attributes by ABC. Also, Header does not the current time by default and in the stopwatch example, so I updated the docs there.

[UriyaHarpeness]

I see typos in many files I open on my PyCharm (it warns about them like in the picture shown), maybe one should take a little time to do a quick scan through the docs to fix all of them.

[UriyaHarpeness]

@davep, can someone review and merge?

[willmcgugan]

Patience please

[UriyaHarpeness]

Of course @willmcgugan, just that the previous PR was merged after 2 minutes~, just wondered if this PR was skipped or missed. No problem.