ports/141855: Bump graphics/pngcrush to latest 1.7.6

[wen at FreeBSD.org]

Synopsis: Bump graphics/pngcrush to latest 1.7.6

Responsible-Changed-From-To: freebsd-ports-bugs->wen
Responsible-Changed-By: wen
Responsible-Changed-When: Tue Dec 22 02:05:39 UTC 2009
Responsible-Changed-Why: 
I'll take it.

http://www.freebsd.org/cgi/query-pr.cgi?pr=141855