BusyBirdBenchmark::StatusStorage: now run_once() measures the time to do get_unacked_counts(), too.
BusyBirdBenchmark::StatusStorage: implement benchmark() class method.
t/StatusStorage_SQLite: add test about how timestamps should be stored in DB.
t/DateTime_Format.t: add tests to check format_datetime() always format in en_US locale no matter what locale is set to the given DateTime object.
StatusStorage::SQLite: use DateTime::strftime() instead of DateTime::Format::Strptime::format_datetime() to boost performance. DT::F::S::format_datetime calls DT::set_locale on the given DateTime object, which takes significant amount of time. The format used in StatusStorage::SQLite is locale-independent, so set_locale can be bypassed.
Add some benchmarking scripts.