Packages information should be in ns metadata, not in attr-map

[fromheten]

Right now the meat of a package is defined in its attr-map (as in this test package).

It would be better to put that in the metadata. Then there is no need for hacks like (nth package 3) (in package.clj.

Instead just calling (meta package) would be enough. Cleaner and one less potential headache for package authors.