Update p5-Text-ASCIITable to 0.20.

Changes from previous:
----------------------
0.20  Wed Nov 30 01:53:22 2011
	- Patch by Salvatore Bonaccorso <carnil@debian.org> fixed spelling errors
	  in manpage.
	- Resolved debian bug #402906.
	- Patch by <FANY@cpan.org> fixes problem with single-lines '0' not being
	  printed.

0.19  Wed Nov 23 12:43:12 2011
	- Added patch by Alexey Sheynuk <asheynuk@iponweb.net> for a big speedup.
	- Added UTF-8 awareness in counting function.
	- Fixed some bugs.