Add new sparse matmul performance tracking test

Existing test for sparse matrix-matrix multiplication is not very representative
fix #5934 – have tested that Base.rat doesn't hang for any Float32.

This code is now truly independent of word-size, although the size
of integer that it uses is native. However, since it doesn't ever
use integer values larger than 2^24, the computation is the same on
32- or 64-bit systems. Scanning through all Float32 inputs takes
about ten minutes; haven't tested all Float64 values, of course.
Merge branch 'master' of github.com:JuliaLang/julia
slight clarification of quadgk docs, as discussed in JuliaLang/ODE.jl#13
Wrap combinatorics memoization caches in let blocks
Merge pull request #5956 from JuliaLang/kms/comb_minor_cleanup

Wrap combinatorics memoization caches in let blocks
Fix performance regression from c330b1d64efa566911cdd20921ca9419e58bacf9

StoredArray is more specific than AbstractVector{T}, so we were
performing unnecessary copies when calling `int` etc. This caused a
regression on the add1 benchmark, since we call `int` in `getindex`.
Merge branch 'master' of https://github.com/JuliaLang/julia into rjg/jstan
Remove scale!{T<:BlasReal}(X::Array{T}, s::Complex)

* Reference: https://github.com/JuliaLang/julia/issues/1868#issuecomment-36004446
Fix #5951
fix #5906

infinite type chain via field instantiation

also a better fix for #5884
Merge branch 'master' of github.com:JuliaLang/julia
print Float16 with 5 digits. fixes #5948

not a perfect fix, but better to spend an extra byte than have wrong output
Fix scale(X::AbstractArray{Real}, s::Complex)

* after removal of corresponding scale! method
* also add tests
Merge pull request #5957 from JuliaLang/kms/fix_scale!

Remove scale!{T<:BlasReal}(X::Array{T}, s::Complex)
Change get getipaddr to default to loopback

Allows building with no external IP address:

62d0b3d4 introduced a dependency on getipaddr(), which previously raised an error if no
external address was found. This broke bootstrap on a loopback-only network.

closes #5945
removed redundant eltype definitions for darray and sharedarray
Merge pull request #5962 from amitmurthy/amitm/eltype

removed redundant eltype definitions for darray and sharedarray
Fix doc example of @test_approx_eq_eps precision argument 

`e-2` means Euler's number minus two. I guess original author wanted to mean `10^-2`
fix #5966

showcompact() should always be compact; confine the output limit stuff to
array printing