Don't raise W083 if a function never touches the outer scope
Merge pull request #1887 from jshint/valueof-better-funcloop

Don't raise W083 if a function never touches the outer scope
Don't emit W098 for exported labels. Fixes gh-1863

Closes #1863
WIP: add atTop()
WIP: fixup
WIP: Fixup2
WIP: Fixuppppp even more
WIP: More tests
WIP: extend test more
WIP: revert changes which would error when exporting let/const before they're declared

TDZ is confusing :u
Warn when export declaration used outside of global scope.