mk: target triple rename arm-unknown-android->arm-linux-androideabi
Make &self permit explicit lifetimes, but don't really use them
(this will be needed for snapshotting at some point).
Allow custom messages on assert statements
auto merge of #5426 : nikomatsakis/rust/issue-4846-lifetimes-in-expl-self, r=pcwalton

(this will be needed for snapshotting at some point)

r? @pcwalton
librustc: adjust logic for cfg attribute and add not predicate.
Tests for cfg attribute.
rewrite the tutorial section on boxes
auto merge of #5428 : thestinger/rust/tutorial, r=catamorphism

My goal is to explain the underlying concepts first (destructors and then ownership) with plenty of step-by-step examples, so that thoroughly explaining the semantics of mutability, boxes, moves, etc. is a breeze. I'm trying to avoid the comparisons with C++ that were done before, because this should be approachable for people coming from any language. C++ programmers already know these concepts so they aren't the audience that needs to be catered to. Comparisons with other languages can be done in separate documents (like [this one](https://github.com/mozilla/rust/wiki/Rust-for-CXX-programmers)).

This still needs examples for ownership (inherited mutability), owned boxes and managed boxes.
Update run-pass/cfg-on-items.rs

Make comment describe actual behaviour.
auto merge of #5436 : alexcrichton/rust/assert-message, r=pcwalton

This would close #2761. I figured that if you're supplying your own custom message, you probably don't mind the stringification of the condition to not be in the message.
Fix pretty printing for cfg test.
compiletest: Make pretty tests actually use compile-flags.
Mark cfg test xfail-fast since check-fast doesn't understand compile-flags.
auto merge of #5350 : yichoi/rust/pull-0313-2, r=graydon,pcwalton

FIX #5330

rename arm-unknown-android to arm-linux-androideabi
auto merge of #5410 : luqmana/rust/cfg-and, r=graydon

This adopts the syntax from #2119. No more annoying workarounds involving wrapping in mods!