[PATCH v2 26/32] sandbox: sdl: Move to use SDL2

[sjg at google.com]

Sandbox currently uses SDL1.2. SDL2 has been around for quite a while and
is widely supported. It has a number of useful features. It seems
appropriate to move sandbox over.

Update the code to use SDL2 instead of SDL1.2.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

Changes in v2: None

 .travis.yml            |   2 +-
 arch/sandbox/config.mk |   2 +-
 arch/sandbox/cpu/sdl.c | 279 +++++++++++++++++++++++------------------
 doc/arch/sandbox.rst   |   2 +-
 4 files changed, 158 insertions(+), 127 deletions(-)

Applied to u-boot-dm, thanks!