More messages in the build script. Some

improved clarity of the code. Change of
semantics: the system for the very moment
does not fail upon the failure of the
packaging process of a single package.

This will become a paramter to set with
a very soon further commit.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/cran2deb@331 edb9625f-4e0d-4859-8d74-9fd3b1da38cb