Improve IEx out of bounds message
Fix bug on `Regex.scan/3` when capturing groups and the regex has no groups
Document issues and improve IEx booting process
Improve inspect docs
Improve String.split and Regex.split docs

Include examples showing that splitting with an empty pattern results
in a final (trim-able) empty string as discussed in #1688.
Merge pull request #1689 from bruce/string-regex-empty-split-docs

Improve String.split and Regex.split docs for empty patterns.