pkg2: make package removal safer by moving deleted pkgs to `.trash`.
fix signif() of 0.0. part of #3497
update helpdb.jl
Fix #3522
Merge branch 'master' of github.com:JuliaLang/julia
improve Array sizeof()
error on sizeof for Type{Symbol} and Type{<:Array}
closes #3490
fix front-end bug in int literals on 32-bit
probably fixes #3520
fix freebsd regression caused by 9582f99671fccaec5bc225f0aa0a660d712bbb44
make `collect` work even for iterables that don't provide length.

This also defined eltype for RegexMatchIterators, making it possible
to write collect(eachmatch(re,str)) for matchall(re,str). See #3525.
A missing space was messing up the [Clark61] link
Fixed a redundant operator in Differences from R section.
Merge pull request #3530 from karbarcca/patch-1

Fixed a redundant operator in Differences from R section.
Merge pull request #3529 from karbarcca/patch-2

A missing space was messing up the [Clark61] link
Proper julia-level I/O initialization

Fixes #2946
Fixes #3416
fix build when neither 'gcc' or 'clang' exist

cc @vtjnash
Fix performance regression for writing Arrays to files
add a style point, and clarify perf tip on declarations
Introduced WorkerSet. Also closes #3515