Flag new/updated Sandcastle examples

[pjcozzi]

Right now, users have to look at CHANGES.md or I guess the file timestamps to see what new examples are in a release.

It would be cool if there was a Sandcastle tab (or other type of sorting / highlighting) where it is easy to discover the new / significantly updated examples.

Could maybe even automate it as part of the build.

Folks were asking for the same thing for three.js at GTC

[mramato]

For automation, this should be easy by having createGalleryList look at new files since the previous release git tag.

[emackey]

This is a great idea. Probably shouldn't use file timestamps for this though. Git log can identify what's changed lately in a particular branch, or we could manually flag some each release.

[emackey]

For example, if a developer has been working on a branch that has changed demos, and then swaps back to master to build a release, the datestamps on those files will get touched to "now" as the demos are reset back to their old master state. They would be incorrectly flagged as new.

Likewise, on a fresh clone, everything is new.

[mramato]

Just do: git diff --name-only --diff-filter=A 1.43 HEAD Apps/Sandcastle/gallery/*.html and you're done.

[emackey]

@mramato That's perfect.

[mramato]

PR incoming.