Add hy_query_filter_downgradable and hy_query_filter_upgradable.
Fix comments in query.c
py: add downgradable and upgradable kwargs to _hawkey.Query.filter.
switch over to the written solv files to save memory
use REPO_LOCALPOOL when loading the filelist extension

Otherwise all of the directory component ids pollute our
main pool.  And repo_add_solv is faster this way, too.
call hy_repo_link when setting the appdata of the system repo

Otherwise our repo data is freed prematurely.
also set the repodata id if an extension is loaded from the cache
rewrite repos after calling addfileprovides

This should speed up operation of the library users quite a bit.
refactor rewrite_repos function
cosmetic: some cleanups of 0e4327c.
Add forgotten queue_free()s from bd3a2ae.

Discovered by mls.
New version: 0.4.13
build: 0.4.13-1
cosmetic: fixed sliced changelog lines in spec file
implement updateinfo caching

Things are a bit tricky, as the updateinfo is not an extension
for existing solvables, but contains its own set of solvables.
libsolv should offer more support for this kind of setup.
logging hawkey version number.

Related: RhBug:1071404
logging: log checksums of written/loaded repositories. (RhBug:1071404)
doc: fixed typo
fixed clang warning of uninitialized variable
Expose hy_arch_detect().

Related: RhBug:1072972