Fix JuliaLang/julia#6665

Provides airyx in addition to bessel[jyikh]x
Tweaks to StepRange: Take 2
Updates following discussion in JuliaLang/julia#6665

Rather than introducing bessel[hijky]x functions, introduce optional
positional argument to bessel[hijky] and airy for scaled version.
deprecate readsfrom/writesto in favor of simply using open on AbstractCmds, and support: open(cmd, mode) do io ... end
better rearrangement of try/catch block in open(f, cmds)
rm obsolete writesto docs
automatically NULL-terminate UTF16 data for passing to Windows (and similar) APIs
NULL-terminate UTF32String data for consistency; deprecate UTF32String(c::Char...) in favor of utf32(c...); add conversion to UTF32String from binary data that looks at the BOM
NEWS updates for UTF16String and UTF32String
added utfXX(ptr[,len]) functions analogous to bytestring, added WString and wstring aliases to make wchar_t* APIs usable
fix utf32/UTF32String mixup
Improve documentation for bytestring()

Fixes #7036.
Merge pull request #7048 from nalimilan/bytestring

Improve documentation for bytestring()
better behavior for float(array) and complex(array). fixes #6422

also add a few inbounds declarations
Merge branch 'master' of github.com:JuliaLang/julia
add deprecation for UTF32String(s::String)
Enable incremental completion of latex symbols

If there is no whitespace between the nearest `\` and the cursor, try to complete a latex symbol or its name *instead* of a Julian name.  This allows for interactive discovery of latex names, but whitespace is required for completion of a Julia name. Note that if these completions were instead *appended* to the Julia options, they have to display without the leading \. I found that to be confusing when mixed in with the Julian names.

If the word matches a latex name exactly, it replaces it with the symbol. Otherwise, it attempts to complete the latex names. While there are some names that are prefixes to other names, I don't find this to be too jarring. It does effectively "shadow" the longer names, making them harder to discover.
reorganization of reducedim.jl

Nothing was changed. I just moved stuff around, to make it easier for future maintenance and updates.
fix #7049, regression due to aff4f88bc9a772ee67e90afbda2984a69e08b72c
Remove superfluous comparison