[Aux] Implicit bool conversion from log record allows not to clear attributes list explicitly.
[API] Added embedded datetime mapping from its raw value to string representation. This involves using already implemented fast datetime generator (~1.5 times faster than strftime).
[Aux] More comments. Code style.
[Unit Testing] Skeleton for keyword testing added.
[Aux] Date Time generator now can format microseconds.
[Unit Testing] Some tests added.
[Aux] These values are meant to be constant.