add notice about compatiblity with N Preview (bug:27830549)
improve linux 32-bit library information (bug:27962189),
add a note about JDK 8 compatibility on Mac,
and a few other edits to installation guide and system reqs.

Change-Id: Ief5c3420a0f17a4d8cf97cc1211d1fd77c4b825b
2 files changed