[python3/en] Clean up confusion between % and .format()
fix import of io/ioutil, run gofmt

generated/downloaded file doesn't work with "go run". it's missing ioutil.
ran gofmt which uses tabs (width=8) for formatting. longest line is 85
characters now. removed whitespace.
Mention that Python 2.5-style string formatting still works in 3
Update swift to beta3

Updated to beta3, new array declaration style,".." and a few other modifications.
Merge pull request #675 from adambrenecki/py3_format_fix

[python3/en] Clean up confusion between % and .format()
Merge pull request #677 from uraimo/patch-1

Update swift to beta3
Merge pull request #676 from heyalexej/patch-1

fix import of io/ioutil, run gofmt