Add id to aliased method properly. Fix #8363

git-svn-id: http://jp.rubyist.net/svn/rurema/bitclust/trunk@5882 018432c1-2f1c-0410-ba7c-d424024924b7
Define ProgressBar alias of BitClust::SilentProgressBar if progressbar gem doesn't exist

git-svn-id: http://jp.rubyist.net/svn/rurema/bitclust/trunk@5883 018432c1-2f1c-0410-ba7c-d424024924b7
Version 0.7.0

git-svn-id: http://jp.rubyist.net/svn/rurema/bitclust/trunk@5884 018432c1-2f1c-0410-ba7c-d424024924b7