Add a clone method to TensorType and its equivalents.
Get rid of typeConstructor in Scan.
Remove struct_id and use the node name.

It is suitably unique and, more importantly, shared with the rest of the methods.
Add print during unit test to help preventing timeouts
Document the clone() method.
Merge pull request #2342 from abergeron/multi_fixes

Multi fixes (pieces of the multi-gpu code)
Merge pull request #2344 from carriepl/test_too_long

Add print during unit test to help preventing timeouts