Make number of workspaces dynamic (no longer limited by 10)

Warning: This is not yet thoroughly tested, so be prepared to
encounter some segfaults. Please enable logging and coredumps,
so we can fix bugs quickly.

src/manage.c

@@ -335,7 +335,7 @@ void reparent_window(xcb_connection_t *conn, xcb_window_t child,
                         }
 
                         LOG("Changing container/workspace and unmapping the client\n");
-                        Workspace *t_ws = &(workspaces[assign->workspace-1]);
+                        Workspace *t_ws = workspace_get(assign->workspace-1);
                         workspace_initialize(t_ws, c_ws->screen);
 
                         new->container = t_ws->table[t_ws->current_col][t_ws->current_row];