[gentoo-portage-dev] [1/3] Cache subsystem rewrite

[Brian Harring]

This patch is the actual replacement cache subsystem.

Cache db backend classes are now designed as repository centric, 
instead of category centric.  Reasoning is that a cache should be 
standalone, should be able to specify single obj for a repo, and it 
allows moving the eclass cache into the cache backend, instead of 
having it seperated (and incredibly slow).

anydbm, flat_hash, metadata (rsync's metadata/cache), flat_list are 
all reimplemented.

Addition of a sql_template class, and a sqlite implementatin for 
testing the sql_template class.

Right now... those are slow.  Comes down the fact stable portage can 
only ask the cache for a single cpv at a time, so it's not exactly 
leveraging the power of a select statement.  Inclusion of the sqlite 
class can be moved to another package, although sql_template should 
remain.

Finally... cache/util.py .  This module holds code for doing cache X 
-> cache Y cloning efficiently, while providing hooks for user code to 
register callbacks (implementation of percentage counts, every N 
merged, etc).
~harring