1. Older articles showed up on refresh, since the existing buffer was
not cleared
2. Same articles would show up sometimes while scrolling since order of
loading was not guaranteed.
3. Repetitive calls were being made when the user reached bottom, making it
unreadable due to too many re-renders (also related to 2)

Download images on background thread in sync, fix notification image cache

Update dependencies, make support libraries consistent

Fixed Body followers issue

This allows using cached images for notifications

# Conflicts:
#	app/src/main/java/app/insti/fragment/BodyFragment.java

Fix notification style, LED color on marshmallow

Remove cardCornerRadius from body/event headers

Generify fragments, add rich notifications