Fix makefiles

Using `cp` to install the documentation and locale file resulted in unpredictable permissions of the installed files.  (`cp` seems to use a combination of the permissions on the original file and the current umask to determine the permissions of the destination file.)  I discovered this issue while working on debugging my Arch packaging script.  Simply using the `install` command like everywhere else allows us to specify the correct file permissions.

Additionally, I discovered that `lib/makefile` was getting installed along with `lib/kdialog.sh` into `/usr/share/think-rotate` due to the overly broad wildcard.  Restricting the wildcard to `*.sh` solves the issue.