Issue 1736 reject UPC/EAN less than 8 chars

git-svn-id: https://zxing.googlecode.com/svn/trunk@2871 59b500cc-1b3d-0410-9834-0bbf25fbcc57
Issue 1751 add unistd.h for getpid()

git-svn-id: https://zxing.googlecode.com/svn/trunk@2872 59b500cc-1b3d-0410-9834-0bbf25fbcc57