add pass-to-the-left character selection

rules/cs.tex

+When handing out the premade character sheets, hand out the characters one at a time, to the player on your left.
+
+\begin{itemize}
+  \item
+  Take the top character and give a brief overview.
+  \item
+  Hand it to the player on your left.
+  They can either accept the character, or pass it to the next player.
+  \item
+  If a character returns to you, put it back in the \gls{characterPool}, at the bottom of the pile.
+  \item
+  If \pgls{pc} dies, the player selects another character from this pool.
+  \item
+  Any allies which enter the game become part of this pool.
+\end{itemize}