Add reduce and sort functions to version ctrl
Rename argument --no-cache to --no-save

Short version is still the same
Fix emptyness checks of pkg{name,ver} in update
Fix upstream check not done in update mode

Previously update mode never call upstream check function and only use cached
data.

Now it always call upstream check and only save it if -S is omitted
Add ch as aliase of check mode
Move list subcommand into command

no more avc list config but avc config
no more avc list cache but avc cache
no more avc list modes but avc modes
Allow list of packages to be filterd in cache and config modes
Add mode to display raw cache
Dynamically detect check against modes