Avoid requiring PHP's timezone settings to be set

[binki]

PHP makes a lot of notice noise when it hits the strtotime() function and the user hasn't set a timezone. This is because there's a chance that the string being parsed is not a UTC-formatted date. I think that since S3 only gives out dates in UTC, PHP is being silly in requiring that a timezone be set. However, there is no utcstrtotime() function provided by PHP which would be happy to parse timezone-independent (i.e., UTC) dates into unix timestamps.

These two commits avoid this issue. The first uses libcurl's own date parsing for handling an HTTP response's Last-Modified header. The second locally uses a UTC DateTimeZone object when parsing dates stored in the XML documents.

[tpyo]

Thanks for this. Just got back from holiday so still trying to catch up! Will examine, test and hopefully merge soon.

[iazi]

Totally agree with that one