object classification: messages are now formatted
Merge pull request #340 from burgerdev/oc-messages

object classification: messages are now formatted
tracking: added cplex timeout option
show exceptions in dialog boxes
Do not check for the type of certain instances but use try-except to check for attributes. Was broken due to datasource decorator. Fixes #342
implement cache memory usage dialog and status bar
opening a project can take some time: show wait cursor, status msg
remove dead code
restoreOverrideCursor() is the correct usage

...otherwise, none but the arrow cursor would be shown
subsequently
debug: time the project loading
bad objects warning dialog works. fixes #343.
object extraction returns features in a nested dictionary.

object extraction serializer works with new features format.
object workflow uses logging instead of print statements
applet serializer uses logging
fix the object extraction test
Added a feature selection dialog to the object classification gui.

closes issue #275.
correct the first 2 tests of object classification
fix all object classification tests
renamed feature slots to make them more obvious
cleaning up object extraction tests