carving: for "done seg" layer, use default16 colortable

This gives better distinguishable colors for the first 16 objects
minor cleanup
fixed integer overflow in array shape to size
Finally putting object workflow in master.

* Workflow uses latest ilastik changes, such as lane functionality.

* Object Extraction functionality no longer duplicated in object
  classification and tracking workflows.

* Dirty propagation works correctly for labeling.

* updated tests.

* Supports multiple forests in parallel.

* Serialization uses SerialSlots functionality, including new
  SerialDictSlot for labels.
simpler solution to calling setValue() with rtype=List
made OpLabelImage a bit more readable
Added pixel classification to object workflow.
ProjectManager: Init a few members early to avoid potential obfuscating errors during cleanup. (If workflow init fails.)
PixelClassification: Batch workflow now re-uses the OpPredictionPipeline operator.
Cluster: Allow batch operators in workflow.
timer: Added @timeLogged decorator.
cluster: Re-ordered imports so that logging is initialized first.
cluster: Added timing log statements to main().
tests: headless: Added timing log statements to help when debugging/performance tuning.
OpObjectClassification: Make sure internal operators are children of the top-level operator.
both raw and binary images visible in object classification gui
combine conditional
OpLabelImage: remove time slice from cache if dirty
completed renaming of buttons in object extraction gui
object extraction serializer supports multiple images.

WARNING: breaks backwards compatibility with existing project files.
re-added old object workflow, for when segmented image already available.