checkheads: import our own copy of the checkheads code I expect enough change and experimental will be made that is it worthwhile having them done in evolution close to the rest of the exchange tests make sense.

compat: work around some filecache bug in 3.8 We are still compatible with this version.

obshashrange: have an half descent wireprotocol command The previous implementation was extremely hacky. The new version is based on the other discovery function and work!

obshashrange: improve message issued during discovery This is a minor new message that help to understand what is going on.

obshashrange: introduce basic sqlite caching Same as for stablerange, this is far from perfect but already a win. The cache is currently extremely volatile, but that will still be a win when doing multiple consecutive request during discovery. Better cache invalidation will happens "in the future".

stablerange: warm cache before using it server side We make sure the cache is fully up to date before starting to use it. Updating all value is more efficient and this give us a single point where we update and write on disk. Hopefully the cache have been kept up to date as we go anyway.