If the device is small, then the "Conenct and trade apps with people near you"
header takes up too much space and we end up not being able to see any nearby
people at all, even if they are in the list. As such, this also removes that
header for "small" and "ldpi" devices. During testing I found that "small" was
not enough, because a 240x400 screen is considered "medium" and there is not
enough space. ldpi seems to be a reasonable metric for "that header is going to
be taking valuable space and should not be shown then".
All larger devices retain the header and seem to look nice.
This also pushes the "Can't find what you're looking for?" message and associated
buttons right to the bottom of the screen. This is more in line with the original
design.
Fixes#604.