add game help for Agent USA (thanks Josh M)

res/GAMEHELP/AGENT.U.S.A

@@ -0,0 +1,25 @@
+  Travel the U.S.A., grow crystals to
+
+cure the infected & destroy the FuzzBomb
+
+
+
+            joystick to move
+
+       button 0 to drop crystals
+
+                   ;
+           move  <   >  move
+                   /
+
+         Space to drop crystals
+
+
+Esc* * * * * * * * * * * * * * * * pause
+
+Ctrl-S * * * * * * * * * * * * * * sound
+
+Ctrl-R * * * * * * * * * * * * * restart
+
+Ctrl-D * * * * * * * * * * * * * * *demo
+[eof]