save / restore scroll position after refreshing list in show/hide blogs view - ref #420
faster syncBlog
faster hide/show all blogs
remove checkForExistingBlog
Merge branch 'develop' into issue/420-show-blogs-selection
add WordPressDB.isBlogInDatabase() method and use XMLRPC url + Blog ID as unique identifier for local blogs
better handling of blogs with a whitespace or empty name
Merge pull request #428 from wordpress-mobile/issue/420-show-blogs-selection

Fix some issues related to show/hide blogs