Align Makefile newline escaping

Align newline escaping just like in other Makefiles.

https://bugzilla.gnome.org/show_bug.cgi?id=727688
Routing: use symbolic direction icons

Symbolic icons is needed for:
  - correctly displaying icons on Hi-DPI screens
  - color inversion
    (ie. selection in a ListBox or when using the dark theme)

https://bugzilla.gnome.org/show_bug.cgi?id=727688
sidebar: Fix alignment of instruction icons

The start/stop icons are 16x16 and the direction hints are
32x32. To ensure aligmnent in the instruction list we need
to make sure the GtkImage always has a 32x32 width.

https://bugzilla.gnome.org/show_bug.cgi?id=727688