Merge pull request #2106 from JuliaLang/jn/win64

support build for (native) win64 -- complete
deprecate expr in favor of Expr
it had a terrible interface since expr(head, a) might make an expression of
any length depending on the type of a (array or not).
fix #2452
minor string tweaks
src/sys.c: Add function to obtain native type alignment information

This handles all the libLLVM machinery outside of the Julia context.
Merge pull request #2454 from pao/topic/alignment-info

RFC: Add function to obtain native type alignment information
src/sys: dynamically detect FZ/DAZ support

With binary builds of Julia becoming more common, it's better to dynamically
detect whether the processor supports SSE/SSE2 and choose the flags based
on that.

For non-x86/x86-64 processors, a stub function is supplied.
test/corelib: add test for denormal flags

Because the dynamic-SSE-test version of jl_zero_denormals uses inline assembler,
and to make sure the arch-specific stuff is done correctly, add a couple of
tests just to make sure things aren't crashing.
Merge branch 'topic/dynamic-zebras'
versioninfo() function. closes #1351
Merge pull request #2434 from JuliaLang/jn/ver

versioninfo(). more or less complete, and hopefully mostly relevant, information on the system running julia -- including julia itself
WINDOWS: fixup the stack before calling error handlers. seems to fix the issue with Ctrl-C on Win64 typically failing