Status page that shows incomplete downloads and percentages completed

Ability to cancel downloads

Video info page which shows description and duration, etc.

Keep connections alive by reusing the same curl handle

Separate the downloader backend from the UI (a separate process?).
Move downloading of all web pages to the downloader thread in order
not to block the UI

Add more video services

Translation of menu contents

Clean up the XML scheme, remove the type attribute from URL tags

Recognize strings that indicate errors on the returned web pages. Many
sites return "no results found" as an HTML page without setting any
HTTP error codes. YLE areena does this for "too many search results"
error, too.

Streaming as an alternative to downloading

Alternative download URLs (Some Youtube videos don't have MP4
version. In this case, the plugin should try to retrieve the standard
low quality video.)
