Add "static" to a bunch of methods that have been missing it, and also add more performance-related logging.

git-svn-id: https://plugins.svn.wordpress.org/broken-link-checker/trunk@892817 b8457f37-d9ea-0310-8a92-e5e31aec5664
Log the runtime of various queries that run during plugin activation.

git-svn-id: https://plugins.svn.wordpress.org/broken-link-checker/trunk@892819 b8457f37-d9ea-0310-8a92-e5e31aec5664