Added support for OnServerInitialized hook.
Added support for OnServerInitialized hook.

Added functionality to run the OnServerInitialized code when a plugin is
reloaded.

ApocDev/Oxide,MSylvia/Oxide,Visagalis/Oxide,bawNg/Oxide,bawNg/Oxide,LaserHydra/Oxide,LaserHydra/Oxide,Nogrod/Oxide-2,ApocDev/Oxide,Nogrod/Oxide-2,MSylvia/Oxide,Visagalis/Oxide