Make the renderSaveButton() function common between edit/new/home

Each of the edit/home/new pages renders its save button differently. This makes it a common function with all the same possible render states (does the document have unsaved changes? Is it already saved? Was it auto-saved?).

- Common save button
- Adds the "save" button to /home page which wasn't there before
- Animates the "save" button in /home and /new when the user makes their first change to signal that yes, you do have to actually click the save button if you want to keep this.
- "reminder... you haven't saved for X minutes" still not functional on /new and /home since that involves more moving pieces.

client/homebrew/pages/newPage/newPage.less

@@ -1,6 +1,12 @@
 .newPage {
 	.navItem.save {
+		.fadeInRight();
+		.transition(opacity);
 		background-color : @orange;
 		&:hover { background-color : @green; }
+		&.neverSaved {
+			.fadeOutRight();
+			opacity: 0;
+		}
 	}
 }