base/bool.jl: `-0.0 + false === -0.0`.
Skip unicode tests if `iconv --version` fails
Add instructions for windows users
- split and rsplit return SubStrings
- faster specialized bytestring for SubString
- updated split usage that depended on old behavior
- updated docs
Iteration over ENV (singleton of EnvHash Dict) returned a SubString
instead of a ByteString.  E.g. isequal(ENV,ENV) threw an error.

Now fixed.
Merge pull request #5544 from JuliaLang/sf/iconvskip

Skip unicode tests if `iconv --version` fails
Fix Issue #5581
Merge pull request #5580 from mauro3/ENVgetBug

Iteration over ENV returns wrong type
Merge pull request #5583 from jakebolewski/jb/fix5581

Fix Issue #5581
base/pkg/git.jl: don't shell out to find .git dir [fixes #4888]
Fix #5586
Tweak tar finding code again
sharedarray - exported sdata, indexpids, subtype changes
Merge pull request #5568 from amitmurthy/amitm/shmem_changes

sharedarray - exported sdata, indexpids. subtype of DenseArray
fix #5584

we were missing a root for a tuple boxed as a function argument
Fix #5587 (quickfix)

Check that the numbers from git are not empty strings before pasting
them into `version_git.jl`.
Merge pull request #5590 from ivarne/quickfix_5587

Fix #5587 (quickfix)
NEWS updates for nextfloat, prevfloat, and setenv
note readline() defaults to STDIN
update helpdb.jl