Advanced inventory's weight and volume columns will now display full
stack values. Oops. Small UI comprovements in addition to this:
* The 'same square!' popup can be ignored as it will pass the next
 keypress (except q and esc) and disappear.
* '0' for weight or volume will appear dimmed.
* current/max number of items displayed at top right
* current inventory total displayed above 'weight vol' header.
* [stack amount] moved to it's own column as it's easier to read.
Merge remote-tracking branch 'dda/pr/986' into dda-master
Style cleanup.