Add Postlight Parser as optional reading view

[tomillr]

In my testing, the Postlight Parser used by the Postlight Reader browser extension seems to work with more websites. Since the parser code is available on Github, woudn't it be possible to add Postlight as an optional reading view in FeedMe? The popular reader app Reeder over on iOS has recently integrated Postlight as well.

[seazon]

Thanks for the feedback. I will investigate it.