fix for get_constant_value

Fix bug when unpickling previous versions of CAReduce

 Fixed crash for unimplemented elemwise gradient

removing a bug

scan_utils.py: Make traversal routines remember visited nodes

Fix check for 0 in values

Thanks @delallea for finding it.

Made size argument mandatory in normal(..)

windows port

dynamic linking to avoid FLS index overrun; "||" instead of "or"

Fixed import error with some numpy version(s)

Add matrix_of_scalars function

Having it default to None suggests it is optional, which is not true (it
will crash when using None).

This import seems to be required on some versions of numpy.

Update link

This bug was reported by Michael McNeil Forbes on the mailing-list.

Typo in try_compile_tmp in op.py

Set Python exception when C code fails

Fixed test values with ``ifelse``