Fix JuliaLang/julia#6665

Provides airyx in addition to bessel[jyikh]x
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.
Merge branch 'master' of https://github.com/JuliaLang/julia into besselx

Conflicts:
	base/math.jl

Keeping track of special functions reorganization
fa742208b31a6640a82a6bf29f97c21cba471ff0
don't shell out for mv
Restore old Associative show method as print
Use basic dict printing as its show method

* The fancy showdict and showkv display method is now called from writemime within replutil.
* The plain dict printing method is simply show
* Plain key and value iterator show methods added, which simply show their collection without any additional markup
* The fancy showdict and showkv now accept keyword arguments to be more inline with showarray.
Revert back to bessel[ijkhy]x function signature

Change as discussed in JuliaLang/julia#6665.

Also fixed JuliaLang/julia#6564 that was omitted in this branch.
help: change the help prompt to "help?>" – it looks rather nice.

It was pointed out at some point that including the `?` in the help
prompt might assist new users in remembering that typing `?` gives
you the help prompt. It also just looks good, imo.
REPL history: use longer, explicit strftime format [fix #7182]
fix type problem that was plaguing #7147
Merge pull request #7147 from mbauman/dict-print

Restore old Associative show method as print
add missing @evalpoly export and test
fix sparse getindex regression.
also replaced binarysearch with methods from sort.jl
ref #7131, #7047
RFC: added performance tests for sparse getindex + a README file
Merge pull request #7177 from mauro3/sparse_perf

RFC: added performance tests for sparse getindex + a README file
Fix function header for full!(Triangular)
disable some optimization passes that are doing more harm than good

ref #6112
Fix #6939
Merge pull request #7046 from hayd/dont_shell_out

FIX don't shell out when you can mv
Merge pull request #6688 from jdrugo/besselx

Fix JuliaLang/julia#6665: adding exp-scaled Bessel functions