Revised plugin: fixes/changes for Topics, Search, Speakers; adds TED Series and Other feeds

[demitrios]

What started as a tweak here and there, ran amok with changes. As I was fixing/changing things, I ended up paring down the code a bit. I'm new to Kodi, but I think the revised addon it worth sharing.

Here are some highlights:

• Reworked "Search" to search for talks or playlists, and added an intervening "New Search" and "Saved Search" so that a saved search string can be added to favorites;
• Changed the "Topics" link to show the playlists and talks from the TED topic page, since there seems to be no good way to access the results of searching from TED's topics page. As a subpar substitute, a context menu "Search" uses the topic as the search string for the addon's search;
• Added "TED Series" to access the series, seasons, and episodes from TED's series page;
• Added "Other feeds" to access some other RSS videos feeds of TED talks;
• Reworked the talk scraper to try a few strategies to get a stream url and subtitles. When stream data are missing, the addon tries to extract a stream url from the talk page's 'external' data keys;
• Changed Fetch class to respect TED's rate limiting responses;
• Where lists of talks tend to be shorter (talks for speakers, talks for playlists, ...) the addon fetches the talk pages. I'm not sure if this is the best approach, as the process is definitely slower, but it seems to play nicer with Kodi's supplied context menu items; and
• Changed "Speakers" to collect and some more info about a speaker.

File, plugin.video.ted.talks-5.1.0-matrix.zip, contains the addon, so you can give it a try.

I apologize for the massive pull request, but my tinkering and lack of planning prevented me from introducing a long list of changes gradually in separate pull requests. If you don't care to merge these changes, please view this pull request as a notice about the availability of the 'matrix-revised' git branch.

[moreginger]

Hi @demitrios and great work :)
I've been looking for someone to take over this plugin and perhaps you've come at the right time? It needs some fresh energy to move things forward and keep things in a good state. What I would suggest is that you fork the repository and reintegrate (if not already done) the changes into Kodi repository, and update the relevant files to point to your fork. I'm happy to offer some any help I can but to be honest I do integration so infrequently myself that I may not be of much help.