[sql gen] Properly create UNIQUE index on non string column. Closes #13728492
Unique was previously detected in a loop triggered only for String columns.
[migration] Drop custom "readfunc" for code.interact in shell
As the referenced bug http://bugs.python.org/issue1288615 got fixed in Python
2.6, this is no longer needed. Furthermore the implementation is not Python 3
compatible (raw_input, unicode).