Add error retry behavior for AJAX requests

[djahandarie]

(This is a stacked PR on top of #188 ~ #192)

Retry up to three times when there are timeouts or the rate limit is exceeded.

[johnmurphy01]

@djahandarie I have just merged in my PR that updates quite a bit of the main code file and also brings the google chrome extension manifest version to 3. If you would still like, please rebase and make the changes against the new codebase. Much appreciated