This is a breaking change as changes the way packages can be given as
arguments to luet.
From this change, the following applies:
- If a package string contains @, the right part is parsed as version
(e.g. foo/bar@1.1)
- If a package contains "/" and no "@", cat/name is applied (e.g.
foo/bar)
- If a package doesn't contain either, is implied its just a name
without category
- If a package contains "=" at the beginning, the gentoo parsing default
is being used ( e.g. =foo/bar-1.1 )
Fixes#154
