Re-imagine Capture.gist
"is cached" now uses Capture.gist to generate keys
Changelog update wrt Hash.(perl|gist)
Clarify Capture.WHICH in Changelog
Make error message for, e.g., chr() more helpful for vvi-ers

Note say() and print() are still LTA compared to STD.pm6
Re-imagine Capture.perl

Make it nicer if now positionals and/or no named parameters.
Remove unnecessary parentheses in Main.pm
Merge pull request #258 from Nami-Doc/patch-1

Remove unnecessary parentheses in Main.pm
On JVM, CORE.setting now compiles comfortably in 800m heap.
Suppress unused warnings for constants. Remove unused local.
Provisionally add "is cas" trait to $@%

Just so I can mark the variables in tests that need to be marked this way.
Revert "Provisionally add "is cas" trait to $@%"

This reverts commit 3648d3d63e8e8d071c131517da4572c21c27f7da.
Expose nqp::readlineintfh to perl6-land

This gives perl6 code access to the readline library, since the REPL
already uses it.