Added scrollbar to reader post detail layout
check for gradle.properties file existence, abort build with an error if doesn't exist
use wordpresslibraries:1.1.2 that checks for source libraries validity
Merge pull request #1648 from wordpress-mobile/issue/1638-better-build-errors

fix #1638 better build errors
Merge pull request #1646 from wordpress-mobile/issue/1645-reader-detail-scrollbar

issue/1645-reader-detail-scrollbar
Merge branch 'develop' into issue/1565-remove-hasactivity