Add case to convert_date for UGE 8.2.0

UGE 8.2.0 has changed all time stamps to now report with millisecond
precision, instead of just seconds as before. This commit adds an extra
case to the convert_date function to handle this case.
Merge pull request #10 from mjrasobarnett/uge-8.2.0

Add case to convert_date for UGE 8.2.0