allow audio components to take a string value

[pngwn]

Audio previosuly expect the value to be an object rather thana string. Audio can now take a string.

Closes #896.

[abidlabs]

The demos work, but I'm still getting issues with the examples that I provided later in the issue. For example

bl = gr.Blocks()

with bl:
    gr.Audio("test.mp3")
    bl.launch()

produces a blank webpage (nothing is shown), instead of an embedded audio file that can be played:

bl = gr.Blocks()

with bl:
    gr.Video("test.mp4")
    bl.launch()

produces an embedded video, but it cannot be played:

Attaching the test files so you can reproduce. test.zip

[pngwn]

There are some inconsistencies with how file data is passed around, I'm going to address that more comprehensively to avoid these issues (that is the source of all of these issues).

[pngwn]

@abidlabs I think those issues should be addressed now, feel free to review/test while i deal with conflicts.

[abidlabs]

Yayy! Everything works LGTM.

(FYI if you merge blocks-dev into this branch, circleci tests should now pass)