Show the best diff share as "best share" and add info to the README.

README

@@ -441,6 +441,15 @@ diminish return performance even if the hash rate might appear better. A good
 starting baseline intensity to try on dedicated miners is 9. Higher values are
 there to cope with future improvements in hardware.
 
+
+The block display shows:
+Block: 0074c5e482e34a506d2a051a...  Started: [17:17:22]  Best share: 2.71K
+
+This shows a short stretch of the current block, when the new block started,
+and the all time best difficulty share you've submitted since starting cgminer
+this time.
+
+
 ---
 MULTIPOOL
 

cgminer.c

@@ -1589,7 +1589,7 @@ static void curses_print_status(void)
 			pool->rpc_url, have_longpoll ? "": "out", pool->rpc_user);
 	}
 	wclrtoeol(statuswin);
-	mvwprintw(statuswin, 5, 0, " Block: %s...  Started: %s  Best diff: %s", current_hash, blocktime, best_share);
+	mvwprintw(statuswin, 5, 0, " Block: %s...  Started: %s  Best share: %s", current_hash, blocktime, best_share);
 	mvwhline(statuswin, 6, 0, '-', 80);
 	mvwhline(statuswin, statusy - 1, 0, '-', 80);
 	mvwprintw(statuswin, devcursor - 1, 1, "[P]ool management %s[S]ettings [D]isplay options [Q]uit",