Documentation improvents for Android Platform Guide

There are some improvements that can be added to the Android Platform Guide, this is about some sections of the guidance that can better explained and more specific, besides of some updates.

-Specify that has to be the eclipse that go along with the Android SDK and no other.
-Android Virtual Devices, specify requirements, update and clarify several instructions to walk through that procedure, in order work with Intel x86 Atom Image.
-Update and improve other steps.