Blocked revisions 67818,67822,67850,67857 via svnmerge

Blocked revisions 67818,67822,67850,67857 via svnmerge

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  r67818 | antoine.pitrou | 2008-12-16 18:38:28 -0600 (Tue, 16 Dec 2008) | 3 lines

  Issue #2183: Simplify and optimize bytecode for list comprehensions.
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  r67822 | mark.dickinson | 2008-12-17 10:14:37 -0600 (Wed, 17 Dec 2008) | 4 lines

  Issue #3439: add bit_length method to int and long.
  Thanks Fredrik Johansson and Victor Stinner for code,
  Raymond Hettinger for review.
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  r67850 | raymond.hettinger | 2008-12-19 03:06:07 -0600 (Fri, 19 Dec 2008) | 9 lines

  Fix-up and clean-up docs for int.bit_length().

  * Replace dramatic footnote with in-line comment about possible round-off errors in logarithms of large numbers.
  * Add comments to the pure python code equivalent.
  * replace floor() with int() in the mathematical equivalent so the type is correct (should be an int, not a float).
  * add abs() to the mathematical equivalent so that it matches the previous line that it is supposed to be equivalent to.
  * make one combined example with a negative input.
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  r67857 | mark.dickinson | 2008-12-19 11:46:51 -0600 (Fri, 19 Dec 2008) | 2 lines

  Fix typo in Python equivalent for bit_length.
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