Add datashape.test() function, test for signed vs unsigned matching
Fix coercion cost between uint64 and int64
Tweak ambiguous overload error message to emphasize the candidates better
Add some more tests for coercion and overloading cases that behave weird
Use operator.index instead of asserting against _inttypes
Add explicit cast of iterator to list for python 3 compatibility
Fix from_numpy extraction of field order
Fix discrepancy in coercion table
Merge pull request #9 from ContinuumIO/coercions

Fix discrepancy in coercion table
Add overloading test of int32 promoting to float32 vs float64
Set the cost function of potentially lossy conversions to 1.5 instead of 1.0
Make zip work in python 3