B3j0f.utils

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- add dependency to the modules six and future and remove version functions.
- use relative imports in UTs.

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- add functions last, itemat and slice in the iterable module.

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- add in the module runtime:
- the function _safe_builtins
- the variable SAFE_BUILTINS
- the functions safe_eval and safe_exec used to eval/exec python code without IO functions.
- add the builtins module in the module version.
- add description of tu, version and runtime in the readme.

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- set stable version.

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- update the module version with python3 and python2 common modules with different names.
- add support of pyhton3.5.

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- add range and raw_input definition in the module version in order to use xrange whatever python2/3 execution environment, and raw_input in python3.