[Resource Timing] Spec updated per Action 3 and Action 4

The Resource Timing specification, http://dvcs.w3.org/hg/webperf/raw-file/tip/specs/ResourceTiming/Overview.html, has been updated per the following two action items:

*         [NEW] ACTION: Jatinder to Update RT spec to be clear on the behavior of what gets included in the RT array. [recorded in http://www.w3.org/2011/03/23-webperf-minutes.html#action03]

*         [NEW] ACTION: Jatinder to Update RT spec to include a HTTP response solution similar to the CORS spec for review by list. [recorded in http://www.w3.org/2011/03/23-webperf-minutes.html#action04]

The changes made to the spec were as so:

*         Added "Section 4.2 Resources Included in the PerformanceResourceTiming interface" and "Section 4.5 Cross-origin Resources" sections.

*         Updated to timestamp wording from NavigationTiming spec.

*         Made all in-document ids (for in-page navigation) standardized and working.

*         Added id attribute to PerformanceResourceTiming interface.

*         Removed loadEventStart and loadEventEnd from PerformanceResourceTiming interface.

*         Added fetchEnd to PerformanceResourceTiming interface.

*         Added redirectStart and redirectEnd attribute details in Section 4.3 (this was previously missing).

*         Removed commented out sections.

*         Updated wording on API interfaces.

*         Half-updated processing model (more to be done).
Removed example from past interface.

*         Added References section.

Thanks,
Jatinder