Added shorcuts to split cell, merge cell above and merge cell below.

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

@@ -319,6 +319,21 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
+                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;                                                
             } else if (that.control_key_active) {
                 that.control_key_active = false;
                 return true;

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

@@ -44,6 +44,9 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'},