DatabaseTools: PhotoDuplicatesFinder: adding hasDuplicate() and setDatabase()
database: renaming PhotoInfoManager to PhotoInfoCache
database: renaming files
database tools: introducing SynchronousDatabase
moving database tools to database; minor fixes
tr: removing requirement of qt linguist
Database: deprecating PhotoIterator & co.

Backend returns now all PhotoInfos
code cleanup
DatabaseTools: SynchronousDatabase: getPhotos() implemented
database: introducing Sha256 filter
database: fix
database: DatabaseTools: SynchronousDatabase: fix
Database: DatabaseTools: finding duplicates
Merge branch 'development'