Normalize name to allow building debian package from CamelCase directory...

I added code in `Pkgr::App` to normalize the application name (which most of the times is the dirname of the rails application root). The normalization "dasherizes" and replace multiple consecutive dashes with a single one.

My rails directory was named `PkgrTest` and when I tried to pkgr it, the Debian source package refused to build because its name starts with capital letter. After normalization, the package name becomes `pkgr-test`.