demandimport: support importing builtins for Python 3
__builtin__ was renamed to builtins in Python 3. If importing
__builtin__ fails, fall back to importing builtins in order to support
Python 3.
demandimport: alias __builtin__ as builtins
Python 3 renamed the __builtin__ module to builtins. In preparation for
supporting Python 3, alias the imported module as "builtins."
bufferedinputpipe: remove N^2 computation of buffer length (
issue4735)
The assumption that dynamically computing the length of the buffer was N^2, but
negligible because fast was False. So we drop the dynamic computation and
manually keep track of the buffer length.
bufferedinputpipe: remove an outdate comment
This comment is the remains of a intermediate implementation using
self._buffer += data
This implementation never made it to the repository and we can safely drop the
comment.