Split delete!(h::Dict,key) into pop!(), delete!()

* Add documentation for pop!(collection, key[, default])
* Deprecate Set add! in favor of push!, for symmetry with pop!
* Also: add push!(h::Dict, k, v) for symmetry with pop!(h::Dict)
Update Dict pop!/delete! changes to latest Julia, remove warnings
Fixed add/add! deprecations.
Converted partition functions from tasks to iterators

* Renamed integer_partitions -> partitions (multiple dispatch!)
* Added partitions(n) variant to generate all integer partitions
* Added npartitions, nsetpartitions functions
* Updated docs
Fix SetPartitions type parameter
Also speed up SetPartitions iteration
Merge pull request #3439 from kmsquire/dict_pop

RFC: Split delete!(h::Dict,key) into pop!(), delete!() (#3405)
Merge pull request #4055 from JuliaLang/kms/partitions

Converted partition functions from tasks to iterators
unexport npartitions, nsetpartiations: use length(partitions(...))
fix possible un-rooted tuples in calls to jl_apply_type
updated NEWS for #4055
un-export ndigits0z, make code_lowered return ASTs
plus some doc updates
Merge branch 'master' of github.com:JuliaLang/julia
update NEWS for #3439
more NEWS updates
fix printf regression due to ndigits0z
there were *no* printf tests in `make testall`, allowing me to break it...
fix Float16 equality and printing
keeps the current show() format, which makes it clear you have a Float16, but
prints in decimal, similar to how we handle unsigned integers.
the printing is done by calling grisu with SHORTEST_SINGLE, which may not
be optimal but is probably correct (won't lose data).
faster convert(::Type{Float32}, val::Float16)
faster Float16 isnan, isinf, ==
add < and isless for Float16
don't overload show for Array{CPUInfo}

I find it more transparent and better style not to hide the fact that something
is an array
Added convert to Ptr from SubString, via conversion to ByteString.  Fixes #4060
Change invalid ulr "foo.bar" -> "foo.invalid"

* Hopefully address NXDOMAIN redirect issue causing #3956
* Still need to address TcpSocket serialization