fix an "unused arg" C++ compiler warning in test suite
fix some typos in comment
remove unused imports in test
fix typo in comment
change test to avoid failures if the GC environment isn't clean before running it
disable IPython history thread in test to prevent dangling thread problem in test suite
prepare release candidate for 0.21
changelog
prepare release of 0.21
Support multiple custom string conversions.
provide "Cython.Compiler.Main.Version" to keep supporting old PyTables versions that import it from there

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extra : transplant_source : %B1%BC%5C%CD%A6%EEmr4B%0F%AF%1C%E0yq9%EA%ADX
safely replace all node references when injecting a literal set for set([...])
whitespace
Fix crash when an exception occurs during module init and the stale module gets used later on (after import failure).
This is fixed by no longer cleaning up the global references to module object and module dict, which obviously has the drawback of leaking memory.
docs: mention that static typing with Py3 signature annotations requires the "annotation_typing=True" directive
fix: not setting module reference to NULL in module init function fails to report exception on return
DOC initialize string with bytes

As-is the example doesn't compile.
Merge pull request #321 from kmike/patch-1

DOC initialize string with bytes
fall back to 'default' Sphinx doc theme on old Sphinx versions that lack the 'nature' theme

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extra : transplant_source : %3E%C7%7C%E0I%E9%84%03%8A%EF%F0z%84%20d%E9%C1%12%AF%3E
copy hexiom2 benchmark over from Python's benchmark suite and apply an initial set of optimisations