Added comments. Removed obsolete lines

git-svn-id: https://plugins.svn.wordpress.org/wp-simile-timeline/trunk@994223 b8457f37-d9ea-0310-8a92-e5e31aec5664
Moved removal of deprecated options to database class

git-svn-id: https://plugins.svn.wordpress.org/wp-simile-timeline/trunk@994229 b8457f37-d9ea-0310-8a92-e5e31aec5664