Enable android on appium build
Add 'def mobile' to multiplatform annotation

Most of our appium related steps are platform independent, so adding 'mobile'
platform. First it tries to load platform specific definitions (ios, android),
if those are not found then 'def mobile' is loaded.
Merge pull request #20 from ggozad/appium-mobile

Add appium 'def mobile' to multiplatform annotation