1. Use Text::ASCIITable. It does a great job!
2. With Text::ASCIITable help, I appended more format to display_sheet,
now the show of Excel sheet on terminal is pretty nice to me :)
3. Add method: sheet_header, display_sheet_header.
4. Change Perl from 5.8.8 to 5.16.3.1063, because I couldn't install
Text::ASCIITable with 5.8.8, too old, cpan complained it.
5. Remove #!/bin/perl from topline instead of package statement in pm
files.
Because pm files don't need the perl statement line.
6. Update pod per changes.