Status.pod: comment about the case when busybird.level is undefined.
timeline.js: practically revert the commit 408fd6079933eac9548f53040beec08db6379866, i.e., window adjust is always disabled when loading statuses (whether they are acked or not). window adjust is confusing. it makes it vague that unacked statuses are actually loaded.
Add POD of StatusStorage::SQLite.