Make userCodeMap part of the class to avoid conversion issues

_userCodeMap was a global variable. It has been integrated inside the classes that use it to avoid undesired interactions.

status

README update

add support for _to*Convertor derived classes

* Final clean-up moved to _cleanup() method
* adding _convert_filter() method

pypy 1.9

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branch : 0.8-dev

pypy 1.8

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branch : 0.8-dev

pypy 1.7

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branch : 0.8-dev

idiomatic 'is None' test to solve issue with EnumItem comparisons

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branch : 0.8-dev

cvc optimization switches as recommended by AV

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branch : 0.8-dev

release date