Web client improvement

[PeterDaveHello]

This PR contains changes as below:

• Update date 3-party libraries
• Clean up dead files
• Fix wrong file permission
• Unify coding style in index.html (using 4 spaces, can be revised)

Please let me know if there is anything needs to be changed here, thanks!

[PeterDaveHello]

@livings124 @mikedld would you like to take a look? Thanks.

[PeterDaveHello]

@ckerr can you help review this one? Thanks.

[ckerr]

👍 on most of the ideas here. Some suggestions:

• Even though the end result would be the same, I'd prefer to see these separate topics broken into their own PRs since they're unrelated. For example, the jQuery / jQuery UI bumps are not related to the indentation styling, and neither are related to the index.html exec flag bugfix. So those all belong in separate PRs.

• The jQuery UI refresh grew the png sizes. I think previously what we did was run them through pngcrush or pngquant to shrink them down ... could you do that on these new icons as well to remove that new overhead?

• I'm not in love with the idea of removing the source versions of the minified files. IIRC we don't bundle them into our release -- and if we do, I'd 👍 a patch that stopped that from happening -- but it's still useful to have them in the repo for reference.

[PeterDaveHello]

@ckerr thanks for the comment, I've updated the PR, please take a look ;)

[PeterDaveHello]

@ckerr do you have a minute to take a look at the revised result? Thanks a lot.

[ckerr]

I realize how long this PR has been in limbo and am trying to clear through some of the backlog. This PR is no longer applicable because jQuery is no longer used in the web client as of #1476.