Zephyr Docker v0.15

Zephyr Docker v0.13.1

Dockerfile: Add g++-multilib to docker image

This commit adds the `g++-multilib` package to the docker image,
which will fix build errors for some 32-bit platforms if we use
this docker image to build test cases on 64-bit machines.

Fixes: zephyrproject-rtos#48

Signed-off-by: Henry Wang <[email protected]>

sdk: update to latest SDK

use 0.10.3 SDK.

Signed-off-by: Anas Nashif <[email protected]>

Dockerfile: Bump to 0.10.0 SDK

Required by:

 zephyrproject-rtos/zephyr@d6eaf5f

Signed-off-by: Andy Doan <[email protected]>