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
Pkg2: slight error/info messaging tweak.
Fixes for 32-bit in stat and stream

Most important is the impact on filesize. Since libuv returns a 64-bit
value on all platforms, we might as well make use of it.
Otherwise 32-bit Julia builds can be needlessly confused about the size of
files.
Merge pull request #3616 from timholy/fix32bit

Fixes for 32-bit in stat and stream
Fix inv for triangular matrices
Update README.windows.md

Clarify python requirements
Fix #3622
handle missing newline after last row
Add fieldoffsets(DataType)
fix #3619, segfault in resize!
Merge pull request #3617 from simonster/fieldoffsets

Add fieldoffsets(DataType)
Update README.windows.md
Revert "Fix inv for triangular matrices"

This reverts commit 247af6bd28773243e9a7dc8437cf1d3780688603.
Revert "Fix #3622"

This reverts commit c339b44a372cc996563a59c50f961eda979632c0.
Fix inv for triangular matrices