Fix the copy dot rake task to actually copy dot files

I found that the copydot rake task never copied any dotfiles. This appears to be due to the use of FileList#exclude("**/.", "**/..",...), which seems to skip *everything*. It seems that due to the way Globs are turned into Regexps for the purposes of the exclude() list, putting "**/." in the list causes ALL files to get skipped/excluded.