Fix alignment of date column in plain text view

This got broken by 2a6a1c63cb21015009fe4fd13f62cdac64e1fe36 and
05a4d686b578794c180ddfaf4945a9d7443f330e.

Signed-off-by: Florian Pritz <bluewind@xinu.at>
implement cache_function to easily cache return values of functions

Signed-off-by: Florian Pritz <bluewind@xinu.at>
cache file/thumbnail responses

Signed-off-by: Florian Pritz <bluewind@xinu.at>
use cache_function() everywhere

Signed-off-by: Florian Pritz <bluewind@xinu.at>