[continuecomment addon] Don't make the line-comment option global

Issue #2182

addon/comment/continuecomment.js

 (function() {
   var modes = ["clike", "css", "javascript"];
-  var continueLineComment = true;
 
   for (var i = 0; i < modes.length; ++i)
     CodeMirror.extendMode(modes[i], {blockCommentContinue: " * "});
@@ -29,7 +28,7 @@
       }
       if (insert != null) insert += mode.blockCommentContinue;
     }
-    if (insert == null && mode.lineComment && continueLineComment) {
+    if (insert == null && mode.lineComment && continueLineCommentEnabled(cm)) {
       var line = cm.getLine(pos.line), found = line.indexOf(mode.lineComment);
       if (found > -1) {
         insert = line.slice(0, found);
@@ -44,19 +43,22 @@
       return CodeMirror.Pass;
   }
 
+  function continueLineCommentEnabled(cm) {
+    var opt = cm.getOption("continueComments");
+    if (opt && typeof opt == "object")
+      return opt.continueLineComment !== false;
+    return true;
+  }
+
   CodeMirror.defineOption("continueComments", null, function(cm, val, prev) {
     if (prev && prev != CodeMirror.Init)
       cm.removeKeyMap("continueComment");
     if (val) {
       var key = "Enter";
-      if (typeof val == "string") {
+      if (typeof val == "string")
         key = val;
-      } else if (typeof val == "object") {
-        if (val.key)
-          key = val.key;
-        if (val.continueLineComment != undefined)
-          continueLineComment = val.continueLineComment
-      }
+      else if (typeof val == "object" && val.key)
+        key = val.key;
       var map = {name: "continueComment"};
       map[key] = continueComment;
       cm.addKeyMap(map);