* Adds a MessageViewer window to Developer Tools.
* Properly destroys message viewer window.
* Adds missing ImGui::End()
* Fixes an oopsie crashing non-windows builds after first run.
* Adds C ABI for displaying a custom message
* Fixes a crash and an issue with messages with SFX.
* Remove some osSyncPrintf's that aren't very useful for this case.
Christopher Leggett