Remove no-opping of arbitrary bindings in INSERT mode.

This list of keys is completely arbitrary, a small subset of Firefox's
supposedly undesirable bindings, and still manages to break three default
bindings on GTK/Firefox. INSERT mode is essentially a pass-through mode. If
that's not desirable then a new enhancement issue should be opened.

Fixes issue #58.

common/content/editor.js

@@ -262,11 +262,6 @@ function Editor() //{{{
     addMotionMap("y"); // yank
 
     // insert mode mappings
-    mappings.add(myModes,
-        ["<C-o>", "<C-f>", "<C-g>", "<C-n>", "<C-p>"],
-        "Ignore certain " + config.hostApplication + " key bindings",
-        function () { /*liberator.beep();*/ });
-
     mappings.add(myModes,
         ["<C-w>"], "Delete previous word",
         function () { editor.executeCommand("cmd_deleteWordBackward", 1); });