Update layer name to VK_LAYER_GOOGLE_CPUTiming (based on #5)

[emrekultursay]

It used to be CPUTiming, but it's more canonical to have a VK_LAYER_$VENDOR_ prefix.

[olehkuznetsov]

Seems as too many commits in this PR

[emrekultursay]

I used stacked PRs:

PR1 - 1 commit
PR2 - 2 commits (based on PR1)
PR3 - 3 commits (based on PR3)

Then as I merge them, I merge them in order 1-2-3. For each one, I rebase first, which gets rid of the already-merged changes from prior PRs.