fix deprecated imports in "Unicode and passing strings" tutorial

make reference from memory allocation tutorial to memory views and array.array support more prominent

get rid of __signature__ property for cyfunctions again as inspect.py in Py3.4 can do the same thing more efficiently all by itself now (only commenting it out because it could potentially become a feature again at some point)

Allow docstrings on cdef classes in .pxd files

Added patch from Nikita to properly parse extension type attribute docstrings in PXD files as well as source files

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extra : rebase_source : a94cc8500c29558b78ee50fbb923cd19a779b33e

tutorial for Python arrays

--HG--
extra : amend_source : 7954c320c39d51cde9ac7d4368258ceb56a3bc2f