macros for turning off bounds checks. fixes #1392

`@inbounds expr` allows bounds checks to be omitted for code syntactically
inside the argument expression.

adds @inbounds to matmul, comprehensions, and vectorized binary operators.
Merge branch 'master' of github.com:JuliaLang/julia into jb/inbounds
Merge branch 'master' of github.com:JuliaLang/julia into jb/inbounds
clarify boundscheck expressions
Merge branch 'master' of github.com:JuliaLang/julia into jb/inbounds
Merge branch 'master' of github.com:JuliaLang/julia into jb/inbounds

Conflicts:
	src/alloc.c
	src/codegen.cpp
	src/jltypes.c
keep unexported macros around. fixes #1735
decided this is not a big enough deal to justify causing any
possible pain.
Pkg2: forgot to specify the git repo to work on in two places.
Generialize float intrinsics

Add support for FLoat16
Change fp intrinsic arg order. Disable Float16
Update mailmap
Merge branch 'master' of github.com:JuliaLang/julia
Pkg2: fix Pkg2.update() -- pull METADATA before Read.available().
Merge branch 'master' of github.com:JuliaLang/julia
Float16: comment out export of float16 function.
Int128 left shift: workaround for #3596 until upstream bug is fixed
Bump libuv again. Fixes #3584 properly
add benchmark for #3142
more 128-bit integer workarounds for shifts on 32-bit systems [#3596]
give proper citation for benchmark algorithm