Rename Date to DateTime.

Rename Date to DateTime.

BUG=http://dartbug.com/1424

Committed: https://code.google.com/p/dart/source/detail?r=17549

[floitsch, 2013-01-08 18:32:51]

Not yet 100% decided, but I have been convinced that Timestamp is not a good
name. Also DateTime is easy to find (both in the documentation, as with the
Editor) for people that are used to Date.
Any objections?

[floitsch, 2013-01-08 18:33:07]

Still missing status-file updates for co19.

[Lasse Reichstein Nielsen, 2013-01-09 16:09:29]

LGTM with useless rambling complaints.

https://codereview.chromium.org/11770004/diff/1/sdk/lib/core/date.dart
File sdk/lib/core/date.dart (right):

https://codereview.chromium.org/11770004/diff/1/sdk/lib/core/date.dart#newcode5
sdk/lib/core/date.dart:5: part of dart.core;
Rename file to datetime.dart

https://codereview.chromium.org/11770004/diff/1/sdk/lib/core/date.dart#newcode16
sdk/lib/core/date.dart:16: abstract class DateTime implements Comparable {
Begin rant:
I still think it's a bad name. It's not the Time of a Date, but really a
DateAndTime. If you combine two concepts in one class, and can't find a single
name for it, maybe it isn't one concept and shouldn't be one class at all.

This is really a wibbly-wobbly timey-wimey thingy that combines an instant in
GMT time with a time-zone and some simplified proleptic-Gregorian calendar
concepts. It has no single concern that it covers, but it rather tries to
partially solve timestamps, time-zones and calendars, and does all three badly
(the first one least so, which is why I prefer Timestamp as name).

I don't think DateTime is better than Date apart from freeing up the "Date" name
for a *real* implementation.
I'd prefer "Time", but that also deserves a better class.
So does "Instant". And "PointInTime" is too long and odd.

So, let's do DateTime. At least we're not the first to do that, no matter how
bad it is.

https://codereview.chromium.org/11770004/diff/1/sdk/lib/core/date.dart#newcode99
sdk/lib/core/date.dart:99: // tools don't yet. Eventually we want to have
default values here.
Comment out-dated? We have a default value in the signature.

[floitsch, 2013-01-22 20:23:39]

PTAL. I kept the Date class for backwards compatibility. At least for some
days/weeks.

https://codereview.chromium.org/11770004/diff/1/sdk/lib/core/date.dart
File sdk/lib/core/date.dart (right):

https://codereview.chromium.org/11770004/diff/1/sdk/lib/core/date.dart#newcode5
sdk/lib/core/date.dart:5: part of dart.core;
On 2013/01/09 16:09:29, Lasse Reichstein Nielsen wrote:
> Rename file to datetime.dart

renamed to date_time.dart

https://codereview.chromium.org/11770004/diff/1/sdk/lib/core/date.dart#newcode99
sdk/lib/core/date.dart:99: // tools don't yet. Eventually we want to have
default values here.
On 2013/01/09 16:09:29, Lasse Reichstein Nielsen wrote:
> Comment out-dated? We have a default value in the signature.

Done.