Correct indentation
Port a simplified versions of pcwalton's "quick reject" mechanism for quickly throwing out method candidates. Yields a 40%-50% improvement in typechecking time as well as lowering peak memory use from 2.2GB to 1.8GB (due to creating fewer types).

Conflicts:
	src/librustc/driver/config.rs
	src/librustc/middle/ty.rs
	src/librustc/middle/typeck/check/method.rs
	src/librustc/middle/typeck/check/mod.rs
	src/librustc/middle/typeck/coherence/mod.rs
Use the quick reject mechanism during trait matching as well. Seems to
yield an incremental improvement (type-checking rustc drops from ~9s
to ~8s).