removed spurious “_supported_types” in complex tests

also fixed the spelling of _skip_types (it was missing the _)
made visible a symbol with all the supported ufuncs
removed the long lists of ufuncs in the tests

Now the tests are based on information in npydecl about
supported ufuncs.
added a reciprocal test for ints that avoids issue #757
Add tests for old numba regressions
Mark test_type_inference test as expected failure
Mark more tests as expected failures for python 3
fix for some test that relied on undefined behaviour

Could cause tests to fail on windows because of NumPy compiler
and llvm producing a different result for that undefined behaviour.
use npy_signbit for signbit ufunc
Merge pull request #769 from numba/ufunc-test-refactor

Ufunc test refactor
Add tests for float->int symbols (esp for 32-bit windows and linux)
Remove 32-bit ftol hack
Remove win32 __ftol2 hack
Remove linux32 __fixunsdfdi hack
Revert "Remove linux32 __fixunsdfdi hack"

This reverts commit e94c957bf337c412dfff8bca58501a26d2d5bc42.
Add __fixunssfdi
Code refactor
Reverting __ftol2 hack which may still be necessary for winXP (need to confirm)
Automatically generate tests for all combinations for int/real conversion
Fix #776 by allowing the dispatcher to create new definition when in an ambiguous case.