fix #1307: back from preferences screen, OnBlogChanged only called previously selected blog is not valid anymore
Merge branch 'develop' into issue/1307-onblogchanged-always-called-settings-return

Conflicts:
	src/org/wordpress/android/ui/prefs/PreferencesActivity.java
fix #1385: s/Blogs visibility/Blogs/
fix refresh button in ManageBlogsActivity
Merge pull request #1364 from wordpress-mobile/issue/1307-onblogchanged-always-called-settings-return

fix #1307: back from preferences screen, OnBlogChanged only called previously selected blog is not valid anymore