Seemingly arbitrary leniency towards commas

[Ictoan42]

Currently some formats allow unnecessary commas others enforce commas in specific places, and others disallow commas entirely. A few examples:

• 12 September 2013 parses correctly
• 12 September, 2013 does not parse
• September 12, 2013 parses correctly
• September 12 2013 does not parse
• September 12 2013 08:00 UTC parses correctly
• September 12 2013 08:00 does not parse
• September 12, 2013 08:00 parses correctly

I'm looking to put together a PR about this (I've already done some brief tests, looking to make it lenient in every case i could think of) but I just wanted to check if this is something you'd be interested in, and check that there aren't any massive pitfalls that I haven't noticed yet that are enforcing the current behaviour