#68 Date formats

[k_uber]

Date formats in Card Details of Twinkle do not follow the date format settings of system preferences (always shows MM/DD/YYYY). Change request to use system preferences.

At the same time, for usability, add the day count (in days) next to the date (days since created, since last tested). (Interval count may not always be the same as last date count, if the test is done later than scheduled).