Add LESS that enables meta-p printing

IPython/html/static/notebook/less/cell.less

@@ -21,6 +21,13 div.cell {
     outline: none;
 }
 
+/* Don't border the cells when printing */
+@media print {
+    div.cell {
+        border-color: transparent !important;
+    }
+}
+
 div.prompt {
     /* This needs to be wide enough for 3 digit prompt numbers: In[100]: */
     min-width: 15ex;

IPython/html/static/notebook/less/codecell.less

@@ -1,4 +1,8
-div.code_cell {
+/* avoid page breaking on code cells when printing */
+@media print {
+    div.code_cell {
+        page-break-inside: avoid;
+    }
 }
 
 /* any special styling for code cells that are currently running goes here */

IPython/html/static/notebook/less/notebook.less

@@ -91,3 +91,10 p {
 .notebook_app #header {
     .box-shadow(@notebook-shadow);
 }
+
+/* Hide the header when printing */
+@media print {
+    #header, #header-spacer {
+        display: none !important;
+    }
+}