Merge pull request #367 from john-hill/PLFM-1828

:)
Merge branch 'release-1.22' into develop
Implement get() and update()
Move configuration to StackConfiguration
Add an important comment
Move more configuration from code to EzidConstants
Allow retrying on DOI errors
Replace null with NotFoundException
try-catch NotFoundException
Merge pull request #370 from eric-wu/develop

Implement get() and update() and config change