Fix some remaining confusion about whether actors take "actions" or execute "commands" (they take "actions").
Author: exarkun
Reviewer: jonathanj
This further reduces the confusing use of the two essentially synonymous words,
"actions" and "commands", throughout the code and in the user interface and
directs players towards "actions".
It does re-introduce the "commands" action as pointer towards the "actions"
action which is probably what confused new players are looking for.