#ttp 330039 EDITOR: Platform-agnostic editor code depends on Windows-only VSAccessor headers
#detail Source code access is now extensible via plugins, so any new editors can be easily added.
#add Added SourceCodeAccess module that routes access via plugins.
#change Moved much of the old VSAccessor code into a new VisualStudioSourceCodeAccess plugin.
#add Added a counterpart XCode plugin & migrated the code from FSourceCodeNavigation (Applescript etc.) into there.
#remove Removed applescript for XCode access (it is now done via code).
#remove Removed source code access functionality from platform layer.
#add Added details customization for source code access settings, so users can choose their own accessor.
#remove Removed dependencies on VSAccessor.
#change Changed API in SWidget to not require building a string to be parsed, instead this acesses and forwards filenames & line numbers.
#extra Tested on Mac by Mark S.
reviewed by Andrew.Brown
[CL 2048697 by Thomas Sarkanen in Main branch]
#proj UE4
#branch UE4
#summary Changed UBT and UHT exit codes to inform about compilation result. The editor is reading exit code of UBT process and changes output message informing if this is a failure due to header changes.
#codereview Robert.Manuszewski
[CL 2044928 by Jaroslaw Palczynski in Main branch]
