Add interface PropertyIdProvider
Update release notes
Update PropertyIdProvider.php
Merge pull request #194 from wmde/propertyidprovider

Add interface PropertyIdProvider
Merge pull request #197 from wmde/propertyidprovider

Update release notes for PropertyIdProvider
added basic tests and entity-patcher documentation
added basic entitypatcher test and implementation
Move patching code out of Entity hierarchy into dedicated patchers
Add extra sitelink patching tests
Do not return a patched instance as this does not work b/c wise
Move fingerprint patching code into dedicated class

This also drops the usage of the deprecated term related methods defined in Entity
Fix indentation issue
split Statement patching code into its own class
split SiteLink patching code into its own class
Simplifications in SiteLinkListPatcher
Replace legacy patching tests with new ones
Remove unused imports
Fix indentation issue