downloader: enable failfast
downloader: use LRO_FASTESTMIRRORCACHE
installonly packages: enable enforcing the limit (RhBug:880524)
update the installonlies list.

most notably, installonly(kernel-module) that ensures kernel-modules-extra stays
installed was missing.
store the expired repos.

dropped by accident earlier.
Support skipping the depsolve stage.
Add iterables splitting function.
Create a YumHistory wrapper.
refactor: Extract transaction IDs/offsets conversion to a standalone method.
Support querying the last transaction ID in the history.
Generalize the PackageMatcher to an ObjectMatcher.
Add iterators exhaustion testing function.
Fix TypeError raised when Base.history_undo called with a nonempty transaction (RhBug:878348)
Enable the "history undo" command.
Move transaction check error output into commands.
Add history-undo-specific transaction check error output.
doc: add documentation for the installonly options.
New version: 0.4.6
build: 0.4.6-1
build: require more recent libcomps and librepo.