* Fix problem with export from newly saved database
Newly created/saved databases (or used with DatabaseWidget::saveAs)
were not exported/imported correctly.
Fixed the problem by reinitializing the ShareObserver on
DatabaseWidget::saveAs.
* Introduce warnings and prevent conflicting shares
Introduced several warnings and errors to indicate improper settings.
Prevent export when a path is used multiple times (only the file path is
checked - may ignore multiple similar ways to reference a share).
* Improve KeeShare integration in DatabaseWidget
Moved initial KeeShare association to constructor.
Introduced Q_UNUSED to indicate need for assignment statement.
Changed build options to use only WITH_XC_KEESHARE and
WITH_XC_KEESHARE_SECURE - WITH_XC_KEESHARE_INSECURE remains as internal
variable to highlight differences (may allow to build schemes later)
Message widget in KeeShare settings for groups is not closeable anymore
Fixed connection to renamed CustomData::customDataModified() signal
Fixed connection to renamed Database::databaseModified() signal
Fixed connection to renamed Group::groupModified() signal
* Add source folder keeshare for sharing with corresponding define WITH_XC_KEESHARE
* Move common crypto parts to src/crypto/ssh
* Extended OpenSSHKey
* Move filewatching to own file (currently in two related classes DelayedFileWatcher and BulkFileWatcher)
* Small improvements for style and code in several classes
* Sharing is secured using RSA-Keys which are generated on demand
* Publisher signs the container using their private key
* Client can verify the signed container and choose to decline an import,
import only once or trust the publisher and automatically import all
data of this source henceforth
* Integration of settings into Group-Settings, Database-Settings and Application-Settings
* Introduced dependency QuaZip as dependency to allow combined export of
key container and the (custom format) certificate
