- For standard view, use ISO 8601 date format.
- For detailed view (i.e. stat), use default Linux date
  format. Also, remove GMT offset to avoid confusion in
  determining source of offset when reading alongside
  the local time zone.

Update documentation

1. File name comparison method:
 - initially ignore white space and punctuation characters
 - run test for numeric values
 - if the remaining substrings match in case-insensitive compare, compare case
 - if they still match, see which one has more prefix symbols
 - if they still match, run a case-sensitive compare on complete strings

2. Fixed xstrcmp() to return diff instead of 0 and -1.