Add compatibility unpickler for python 3, use it in test
First fix in scan_merge: clone each inner graph independently
Merge pull request #1593 from lamblin/fix_py3_unpickle

Add compatibility unpickler for python 3, use it in test
Merge pull request #1591 from lamblin/fix_scan_merge

Fix in scan_merge: clone each inner graph independently
Merge pull request #1592 from yosinski/master

Some doc / tutorial updates