Only create widgets for controls if the controls are non-empty.

This avoids creating checkboxes with no names or dropdown lists with no
entries.
Change Enemies() to default to only counting enemies you have attacked.

To get the old behavior of counting all enemies that are hostile to the
player's group, then use "Enemies(any=1)".

This more closely matches expectations of script writers that want to do
different actions when faced with differing numbers of enemies -- it's
sensible to count adds only when they are in range of your attacks.

This fixes ticket 323 by @hoogoon.
Fix copyright dates for files touched in 2014.