Always open dropped files if possible

[humphd]

Fixes https://github.com/mozilla/thimble.mozilla.org/issues/2316. Try this out and see what you think. One thing I don't love is that it flashes through opening all the files when you import a .zip, which I think is a bit jarring. Maybe we should add some code here to pick the best file to open when you have many and only open that one? For example, prefer an .html but then have a sliding scale for different types.

Please test this multiple ways:

• drag and drop 1 file into file tree
• drag multiple files and/or a folder into the file tree (folders only work in some browsers)
• use bramble.showUploadDialog() and use the drop area and "from computer"
• repeat all of about with a .zip and .tar file

[humphd]

I made a mistake on this, but have fixed it now. Travis should be passing.

[flukeout]

Testing this from the Vancouver airport as I wait for a flight and it works great. Files open as expected after dragging them in.

Another option for the ZIP case would be just to not do this at all. Can we skip doing this for ZIPs? Reason is we can avoid some complexity in trying to figure out the "right file" and also in an archive there are usually a bunch of files, so there isn't this expectation that I want to see that one file open like I would with a single added image etc. In the single-image cases this works great. It's also a good way to discover some of our new viewers for users.

Lastly, after dragging in a file, the viewer opens, but the file it's showing doesn't get "selected" in the File Tree. See below, for a file I just dragged in "_blam.gif"

[flukeout]

Well since I have to add comment if I'm requesting changes:

• Highlight the opened file in the Filetree view
• Don't open any files after importing a ZIP

[humphd]

@flukeout made some changes, still can't get the "select when open" to always work, it's a bug deep in Brackets I can't quite find. However, the zip/tar case should work now.

[flukeout]

Awesome, retesting.

[flukeout]

Hey @humphd - give this a try with a css file. For me, it doesn't open a css file after dragging it in, getting this error in the console...

This is on src/hosted just running brackets in mac after clearing the application storage.

It also throws that error when I try to switch to that file (or, also HTML files) after uploading it. It's cleared up after reloading the editor. I confirmed that this happens only within this branch, and not when running on master.

[flukeout]

Please see comments I left regarding JS error on CSS/HTML files.