file descriptors returned by os.pipe() are from the same pool as file.fileno()
added dup and dup2
further improvements for dup, dup2, pipe, open

changed to make it .net 3.5 compatible
pipe related code is wrapped in FEATURE_PROCESS
dup2 and open allocate lowest available fd
added os.closerange
os.open can open 'nul' file on windows
os.close closes underlying stream only if last fd is closed
added fd_test.py
fixed cp35075 - added unboxing in case of biginteger
other int/long parameters to datetime.replace accept long
Rename decorators -> decorator_list in ast.FunctionDef to make it consistent with cpython ast
date.replace accepts int/long
made time.replace consistent with datetime.replace and date.replace

time.replace with float/double argument raises exception consistent with cpython
Catch failures when closing streams.
Merge branch 'tinker-with-file' into ipy-2.7-maint
Merge remote-tracking branch 'lck/ipy-2.7-maint' into ipy-2.7-maint
Handle any capitalization of NUL in os.open.
Merge pull request #183 from paweljasinski/cp35075

fixed cp35075 - added unboxing in case of biginteger