Raspberry PI / Android a minimal cross-compile configuration

The patch provides a minimal configuration required to cross compile Erlang/OTP platform to Android and/or Raspberry PI using Android NDK. The patch excludes any add-on services required to install OTP platform into target HW due to Android fragmentation and jailbreak requirements (on some devices). However, OTP deployment on Raspberry PI is straight forward using OTP releases, tar ball, etc. 

HOWTO/INSTALL-ANDROID.md provides a guidelines (validated on Linux/MacOS).