core: convert an XXX into a FIXME.
std: Constify the bytes sent to Sha1::input

We are of course never going to modify the data, and this change allows us to
accept data from to_bytes::IterBytes types.
remove apparently-superfluous extra parens from types
Add Peter Williams to AUTHORS
really update mandelbrot to pipes
use newtype struct for devnull rather than type aliased record
fix sugarise-doc-comments.py shebang
add missing $(CFG_PYTHON) prefixes
Change "interface" to "trait" in rustdoc

Closes #4337
Merge pull request #4336 from thestinger/python

fix build for when 'python' is python3
Add test cases (one xfailed, one not)

as per #3601 and #3609
Actually xfail this, unbreak build
Add xfailed test for #3707
clean up condition module:
* use Drop trait in Guard
* fix formatting
* remove bare function in Condition.raise_default
* use moved types instead of borrowed pointers in Condition.{raise,trap}
* import common functions
Fix two minor issues in the tutorial.

Remove an extraneous 'then', and replace 'second' with 'first'.
Add option::get_zero

r=brson

Closes #3797
core: fix windows breakage, r=burningtree.
Make either::{partition, flip, to_result} take their arguments by-value

Addresses an XXX

r=pcwalton
Rename option::get_default => get_or_default, get_zero => get_or_zero
Merge remote-tracking branch 'superoptimizer/master' into HEAD

Conflicts:
	doc/tutorial.md