Fix problem in bracket-matching on the first line

Author: marijnh

lib/codemirror.js

@@ -1173,7 +1173,7 @@ var CodeMirror = (function() {
           }
         }
       }
-      for (var i = head.line, e = forward ? Math.min(i + 50, lines.length) : Math.max(0, i - 50); i != e; i+=d) {
+      for (var i = head.line, e = forward ? Math.min(i + 50, lines.length) : Math.max(-1, i - 50); i != e; i+=d) {
         var line = lines[i], first = i == head.line;
         var found = scan(line, first && forward ? pos + 1 : 0, first && !forward ? pos : line.text.length);
         if (found) {