genetics: Implement correct elapsed time measuring
genetics: Implement correct elapsed time measuring

This adds a resumedTime variable which is used to offset against the
starting time, to prevent the time spent during pauses from counting
towards the total elapsed.

Closes #28.

ChrisCummins/chriscummins.cc,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.cc,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.cc,ChrisCummins/chriscummins.github.io