util: reference __main__ in sys.modules as a sysstr

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.

manifest: use node.hex instead of .encode('hex') The latter doesn't work on Python 3.

pure: use int instead of long Similar to the recent 73aa13bc8dac (revlog: use int instead of long, 2017-03-19).

histedit: inline cleanupnode Move "cleanupnode" (unsafe strip) into "safecleanupnode" so it's impossible to call the unsafe function directly. This helps reduce future programming errors.