[gentoo-soc] Rework porthole for portage API -- week 7

[Detlev Casanova]

Hey everyone !

This week, I've been working on the PackageWrapper class. more and more 
functionalities have been moved and porthole now uses those instances 
everywhere.

Note that they are used to represent a particular ebuild. For example, the 
package list gets its information from a list of str's then, PackageWrappers 
instances are taken from the backend with functions like get_installed(), 
get_masked(), get_best(),...

Now that it is pretty stable, I'll start working on the portage backend again 
to make it use the PackageWrapper system.

Another thing I've been doing is converting the commands file for pkgcore to 
use the pkgcore scripts, it was using portage's so far.

Next week, I plan on working on the portage backend and make it work again.
There is also som caching to do, to avoid having multiple copies of the same 
PackageWrapper (two calls to the same function with the same argument will 
create 2 identical PackageWrapper, which contains all package properties)

I'd also like, if I'm able to stabilize the backends enough, to start working 
on actions.
Even if portage's ones aren't ready, I can already start that.

cheers,

Detlev.