time_t changes for consideration

plus updates to 2 core files and 11 example programs that use time_t
epic epoch work

Made epoch_year a static member with accessor/mutator so that different
epochs can be selected at run time.  This will allow NTP to do its
calculations WRT the NTP epoch, while the rest of the system runs on a
more-efficient epoch.
Added parse method to match operator <<.
Added use_fastest_epoch method to configure time_t to run as quickly as
possible.
Removed timing and old code comments.
Fixed minor bug at for epoch years that don't end in 00.
CosaTime now has numerous tests for clock_t conversions and performance
measurements (log file added).
Use the NTP epoch instead of the default Y2K
Merge pull request #249 from SlashDevin/time_t

time_t support for multiple epochs
Clean up.
Clean up.