Verify, check, validate ISO8601 date formatting in the logger objects, tags

[gigapod]

This is response to this issue:

sparkfun/SparkFun_DataLogger#36

The current ISO 8601 format - which might be from the Artemis OpenLog code base - is using the week-base year formatting code.

It appears this is one of several options for years, which include Calendar date, original data and week date see here

Should check verify the above, which is looking correct. If so, do the following:

• Make two ISO8601 options - a "normal" one and a "week-date" one
• Verify the years being used for all time outputs for the timestamp - the normal versions (non ISO 8601) appear to be using the week-date code also.
• This will require and update to the utility routines for timestamps ...