Class String_Parser adds functionality to specify
a format string that is used to customize the
data records. For time, strftime is used, otherwise
fprintf-syntax is used.

Get the time from data-object represented as string
based on format specifier using strftime

A default value can be specified for Parameters_Reader.
This is useful if some parameters are not specified in
the file.

Set default values for calibration constants that
will be used when unspecified in parameter file.

yday in struct tm_time had to be set by
calling mktime

Previously defined entries of par-file can be
referred to with ${NAME}, and they will be
replaced accordingly when parsing the par-file.

Wait to start filtering until .5s of next second has
just passed.