Updated release notes for 0.11.0
Update to 0.11.0
Merge remote-tracking branch 'origin/master' into 0.11.0-release

Conflicts:
	src/libstd/lib.rs
Merge remote-tracking branch 'origin/master' into 0.11.0-release

Conflicts:
	RELEASES.txt
auto merge of #15343 : alexcrichton/rust/0.11.0-release, r=brson