Add Hash Function For Set
Add Test For Set Hashing
fix #4584
close #4585
add missing fallback method for rsearch. ref #4586
extend isascii() to strings like other character predicates. ref #4586
remove inbounds from fasta benchmark
fix some cases where Unreachable needed to be propagated in codegen

specifically, where an error-throwing expression was passed to an intrinsic
remove non-functioning Reverse iterator. closes #4590
reverse ASCIIString, UTF8String, and CharString eagerly. closes #4586

we still use RevString a couple places internally to avoid copies.
a couple release notes updates
Merge pull request #4572 from fundamental/master

Add Hash Function For Set