* Removed code to invalidate makefiles when adding new source files. UBT should be reliable enough to make this determination itself nowadays, and ignored -invalidatemakefilesonly argument was causing modules to be recompiled.
* Fixed incorrect config section name when determining whether to allow hot reload from IDE. Now prevents hot reload from IDE when live coding is enabled.
* Added error message when trying to add a new class with Live Coding enabled.
* Added error messages when trying to start Live Coding after a hot reload has taken place.
* Added error messages when trying to hot reload with Live Coding enabled.
#jira UE-71253
#rb none
#ROBOMERGE-OWNER: ryan.gerleve
#ROBOMERGE-AUTHOR: ben.marsh
#ROBOMERGE-SOURCE: CL 5403464 in //UE4/Release-4.22/... via CL 5403485
#ROBOMERGE-BOT: ENGINE (Main -> Dev-Networking)
[CL 5417897 by ben marsh in Dev-Networking branch]