Adding calibre. This involved also:
tree469d50873647a7f6fcfd06a839076a6e2cc385f2
-rw-r--r-- 1650 COPYING
-rw-r--r-- 1 STABLE
-rw-r--r-- 4 VERSION
-rw-r--r-- 41 default.nix
drwxr-xr-x - doc
drwxr-xr-x - maintainers
drwxr-xr-x - pkgs