ui: convert to/from Unicode on Python 3 in ui.editor() I considered making this I/O be done in terms of bytes, but that would cause an observable regression for Windows users, as non-binary-mode open does EOL conversion there. There are probably new encoding dragons lurking here, so we may want to switch to using binary mode and doing EOL conversion ourselves.

manifest: refer to bytestrings as bytes, not str Required on Python 3.