TTP# 334923 - EDITOR: Perforce Integration (Move -> Delete + Add instead of Integrate)
New API: Added ISourceControlRevision::GetBranchSource.
Made sure the P4 and SVN providers perform integrates/copies so that history is maintained across file copies & moves.
Also fixed SCC icons not refreshing sometimes until source control operation has completed.
Added new branch icon.
Fixed date display in history.
This required some fairly nasty fixup to get it all working within the Editor copy code path, but the majority of the changes are in the source control providers.
reviewed by Andrew.Brown
[CL 2095604 by Thomas Sarkanen in Main branch]
Instead of using the (cached) state, we cache the brush to use to display the state and only hit the state cache when state changes.
Also updated Execute() calls to providers to only do relative-path conversions if the path is already relative.
Added SourceControlHelpers::AbsoluteFilenames to aid conversion.
TTP# 335201 - ContentBrowser: Improve idle performance
#codereview Andrew.Brown
[CL 2075346 by Thomas Sarkanen in Main branch]
