Have the Pipeline emit finished() when it finishes
Have the Pipeline emit finished() when it finishes

Due to some refactoring, the Pipeline no longer emitted finished()
when it was finished. Because of this, tomviz would never be notified
when state files finish loading, and the "Please wait..." dialog would
not go away.

Emit the finished() signal when the Pipeline finishes to fix this
issue.

Signed-off-by: Patrick Avery <743342299f279e7a8c3ff5eb40671fce3e95f13a@kitware.com>

OpenChemistry/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz