8.2.2 Cache n' fix Release

There have been a number of reports of a corrupt cache message after a uSync import #18. While we don't have a root cause for this, or even if its something uSync is doing or if its deeper in the Umbraco core; we have a couple of mitigations in this release to hopefully negate the issue.

#51 Cache Rebuild - When an import is complete uSync will request a cache rebuild, this should remove any corruptions that might occur.
#49 / #54 Reduce the number of saves a handler makes - during our investigations we discovered internal cache rebuilds can get triggered even if nothing is changed, as such we have brought forward the change checks into uSync so it calls less save methods on items that haven't changed,

We also have a number of tidy up fixes/improvements :

#50 - fix false change positive when content has empty values
#46 - fix attempt to remove containers when they are not empty.
#52 - fix issue wherein certain configs two items with the same name can overwrite files

#48 - Culture-based publishing (publish nodes based on culture)
#47 - Improve the handling of trashed items.
#53 - Improve content handlers change detection (description field)
#55 - Improve the reporting of new property values in the details view