rename app.less to style_noapp.less

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

@@ -1,4 +1,4 b''
-@import "app.less";
+@import "style_noapp.less";
 
 @import "notebook.less";
 @import "celltoolbar.less";

IPython/html/static/style/ipython.less

@@ -12,6 +12,6 b''
 @import "../tree/less/style.less";
 
 // notebook
-@import "../notebook/less/app.less";
+@import "../notebook/less/style_noapp.less";