Fix roku-hdhomerun on SD displays

[pompous-stranger]

I have an older Roku 2100X (XD|S) with 3.1 firmware alongisde a Roku HDMI Stick. They receive OTA TV via a HDTC-2US through the ply server.

When the 2100X is set to 4:3 display, roku-hdhomerun streams but never displays video, because:

"The StreamQuality attribute is used to select streams and indicates if a stream is HD or not. If the attribute for HDBranded is set to true and the stream is HD, the HD icon will show beside the quality dots. If the StreamQuality is set to HD, and the user display type is set to SD, the HD stream will not be selected." (http://sdkdocs.roku.com/display/sdkdoc/roVideoScreen)

Therefore I have added a function (in utils.brs) that detects what display type the roku is set to. StreamQuality is then set to that value so that the stream is played on both HD and SD screen-types. I have also created and added the missing manifest .pngs so the HDHomeRun icon will display on the MainMenu in older firmwares.

Finally, using the same function, and some glue I added to ply server, (https://github.com/pompous-stranger/ply/compare/themacks:master...master) I attached a query to the wallop POST/tune channel method to tell ply what display type it was streaming to, so it could select the optimal SD/HD video transcode for roku-hdhomerun. Something similar could probably be done to wallop. Currently wallop appears to ignore the query in my testing, so this change shouldn't be destructive.