Place package metadata directly in .el files

In the case of single-file packages like this, a -pkg.el is unnecessary.

This commit therefore removes the -pkg.el files and puts the info
directly in the .el files. It also, therefore, adjusts the formatting of
those files slightly in order to be readable by `package-buffer-info`.

(In relation to https://github.com/milkypostman/melpa/pull/864)