pkg: u8g2: smaller patches + comments.

Author: basilfx

pkg/u8g2/README.md

@@ -52,8 +52,8 @@ u8g2_SetDevice(&u8g2, SPI_0);
 ## Virtual displays
 For targets without an I2C or SPI, virtual displays are available. These displays are part of U8g2, but are not compiled by default.
 
-* By adding `USEMODULE += u8g2_utf8`, a terminal display is used as virtual display.
-* By adding `USEMODULE += u8g2_sdl`, a SDL virtual display will be used. This is only available on native targets that have SDL installed.
+* By adding `USEMODULE += u8g2_utf8`, a terminal display is used as virtual display, using UTF8 block characters that are printed to stdout.
+* By adding `USEMODULE += u8g2_sdl`, a SDL virtual display will be used. This is only available on native targets that have SDL installed. It uses `sdl-config` to find the headers and libraries. Note that RIOT-OS builds 32-bit binaries and requires 32-bit SDL libraries.
 
 ### Example
 ```

pkg/u8g2/patches/0001-u8g2-add-riot-os-makefiles.patch

@@ -1,4 +1,4 @@
-From 96295dd6b68eee06e736ccf84b3225682a912230 Mon Sep 17 00:00:00 2001
+From 09dad731ec608609836aae37ab32fbceec8f3eaa Mon Sep 17 00:00:00 2001
 From: Bas Stottelaar <[email protected]>
 Date: Tue, 24 May 2016 20:17:39 +0200
 Subject: [PATCH 1/2] u8g2: add riot-os makefiles.

pkg/u8g2/patches/0002-u8g2-add-riot-os-interface.patch

@@ -1,4 +1,4 @@
-From 454b1b8fd9732642a74d1269b74a569e418ae9db Mon Sep 17 00:00:00 2001
+From e6838299ea324752a559ce1a583c7e2259a121b8 Mon Sep 17 00:00:00 2001
 From: Bas Stottelaar <[email protected]>
 Date: Wed, 22 Jun 2016 18:04:31 +0200
 Subject: [PATCH 2/2] u8g2: add riot-os interface.