Added '-' as a shortcut for splitting cells.

IPython/html/static/notebook/js/notebook.js

@@ -319,21 +319,11 b' var IPython = (function (IPython) {'
                 that.undelete();
                 that.control_key_active = false;
                 return false;
-            } else if (event.which === 55 && that.control_key_active) {
-                // Split cell = w
+            } else if (event.which === 189 && that.control_key_active) {
+                // Split cell = -
                 that.split_cell();
                 that.control_key_active = false;
-                return false;
-            } else if (event.which === 56 && that.control_key_active) {
-                // Merge cell above = e
-                that.merge_cell_above();
-                that.control_key_active = false;
-                return false;
-            } else if (event.which === 57 && that.control_key_active) {
-                // Merge cell below = r
-                that.merge_cell_below();
-                that.control_key_active = false;
-                return false;                                                
+                return false;                                               
             } else if (that.control_key_active) {
                 that.control_key_active = false;
                 return true;

IPython/html/static/notebook/js/quickhelp.js

@@ -32,6 +32,7 b' var IPython = (function (IPython) {'
             {key: 'Ctrl-m v', help: 'paste cell'},
             {key: 'Ctrl-m d', help: 'delete cell'},
             {key: 'Ctrl-m z', help: 'undo last cell deletion'},
+            {key: 'Ctrl-m -', help: 'split cell'},            
             {key: 'Ctrl-m a', help: 'insert cell above'},
             {key: 'Ctrl-m b', help: 'insert cell below'},
             {key: 'Ctrl-m o', help: 'toggle output'},
@@ -44,9 +45,6 b' var IPython = (function (IPython) {'
             {key: 'Ctrl-m m', help: 'markdown cell'},
             {key: 'Ctrl-m t', help: 'raw cell'},
             {key: 'Ctrl-m 1-6', help: 'heading 1-6 cell'},
-            {key: 'Ctrl-m 7', help: 'split cell'},
-            {key: 'Ctrl-m 8', help: 'merge cell above'},
-            {key: 'Ctrl-m 9', help: 'merge cell below'},
             {key: 'Ctrl-m p', help: 'select previous'},
             {key: 'Ctrl-m n', help: 'select next'},
             {key: 'Ctrl-m i', help: 'interrupt kernel'},