sqlite metadata for rpm-md

[Anders F Björklund]

Later versions of Fedora has moved from the .xml.gz metadata to use .sqlite.bz2 instead. Smart might support the new database format for yum metadata as well as the old

[Anders F Björklund (afb)]

Loading pathlist/changelog data from .sqlite is faster than .xml,
but for parsing primary into native format could be even slower.

[Rehan Khan (rasker)]

Tested this branch:

Started with no cache and no repo data.

Update worked fine.
Updating sqlite db -> cache worked fine but is slow. (perhaps some psyco optimisation or a c sqlite python module? yum seems to work at a reasonable speed, I guess using the yum-metadata-parser, could this be leveraged?).
Install package/reinstall package/remove package all worked fine.
close/reopen smart also works fine.

(Well, after the initial sqlite -> cache import the sqlite data is not directly used)

I did not test update a second run of update yet as I will have to wait for new repo data.

[Anders F Björklund (afb)]

Mostly working