Fix 12hr time formatting

[molovo]

Currently, the time formatting directives %I and %l return 0 (zero) for midnight/midday, yet in most locales 12 would be preferred. This PR adds a simple ternary check to return 12 when time.hour % 12 resolves as zero.

[asterite]

Thank you! Would be nice to see how other languages behave here.

Also, without specs this is impossible to merge.

[oprypin]

Python 3.6.2
>>> import datetime
>>> datetime.time(0, 0, 0).strftime("%l %p")
'12 AM'
>>> datetime.time(12, 0, 0).strftime("%l %p")
'12 PM'

[Sija]

Ruby 2.4.1

DateTime.new(2015, 1, 1, 0, 0, 0).strftime("%l %p")
# => "12 AM"
DateTime.new(2015, 1, 1, 12, 0, 0).strftime("%l %p")
# => "12 PM"

[molovo]

@asterite 👍 I've amended my original commit to add specs

[molovo]

Hmm, is that failure on x86_64 because of something I've done? It passed on i386

[oprypin]

VM ran out of memory

[Sija]

🕚 to 🚢

[asterite]

@RX14 Thank you! Your help is really appreciated 🙇

@Sija And you too! You have an 🦅 pair of 👀 for everything! 🌈