Give the pretty-printer access to info about infixes
javascript: removeIDs should remove nested identities
Respect precedence and associativity for infix ops in pprint

Fixes #1050.
Fix line breaks in display of :t at REPL
Merge pull request #1173 from raichoo/javascript

javascript: removeIDs should remove nested identities
Fix interactive editing and tests

The pretty-printer fix broke parens in interactive editing.
Allow the big startup banner to be disabled

This is done by adding `:set nobanner` to the init script.

Fixes #590.
Merge pull request #1175 from david-christiansen/pprint-assoc

Fix associativity in pretty-printer
Merge pull request #1176 from david-christiansen/init-banner

Allow the big startup banner to be disabled