fix #1139: call RefreshBlogContentTask on first blog when user login
call ApiHelper.RefreshBlogContentTask on blog changed
remove call ApiHelper.RefreshBlogContentTask in PostsActivity since it's now done on blog changed
Merge branch 'develop' into issue/1139-refresh-blog-options
move RefreshBlogContentTask async task execution from a background thread to UI thread - also fix useless refreshContet in case of blog list fetch error
check if returned blog id is an int
Merge pull request #1528 from wordpress-mobile/issue/1139-refresh-blog-options

fix #1139: call RefreshBlogContentTask on first blog when user login