Inconsistent labels in the interface

[geoffgeoffgeoff3]

Teppei says ...

It might be nicer if the positions of next and prev buttons
are swapped (see the attached).
(Maybe this is just because I'm right-handed.)
Also, capitalization should be consistent (e.g., Prev -> prev).
I'm not sure if these are specific to the containerized version, though.

[AndresCdo]

I've nearly finished unifying the button components, they should be consistent now.