Print and use correct port after binding (fixes #571).
Print and use correct port after binding (fixes #571).

Previously GlowServer#getPort() would return the wrong port if the server
was instructed to bind to port 0 (any available port). This commit
resolves that issue by storing the port that the server actually bound to
and returning that. The bound port is also printed to the log.

LukBukkit/GlowstonePlusPlus,keke142/GlowstonePlusPlus,GlowstoneMC/GlowstonePlusPlus,Postremus/GlowstonePlusPlus,BlazePowered/Blaze-Server,GlowstonePlusPlus/GlowstonePlusPlus,Postremus/GlowstonePlusPlus,Tonodus/WaterGleam,GlowstonePlusPlus/GlowstonePlusPlus,GreenBeard/GlowstonePlusPlus,jimmikaelkael/GlowstonePlusPlus,GreenBeard/GlowstonePlusPlus,LukBukkit/GlowstonePlusPlus,kukrimate/Glowstone,Postremus/GlowstonePlusPlus,kukrimate/Glowstone,Tonodus/GlowSponge,Tonodus/GlowSponge,GreenBeard/GlowstonePlusPlus,BlazePowered/Blaze-Server,keke142/GlowstonePlusPlus,GlowstonePlusPlus/GlowstonePlusPlus,GlowstonePlusPlus/GlowstonePlusPlus,Tonodus/WaterGleam,GlowstoneMC/GlowstonePlusPlus,keke142/GlowstonePlusPlus,Postremus/GlowstonePlusPlus,keke142/GlowstonePlusPlus,GlowstoneMC/GlowstonePlusPlus,LukBukkit/GlowstonePlusPlus,jimmikaelkael/GlowstonePlusPlus,Tonodus/WaterGleam,Tonodus/GlowSponge,Tonodus/GlowSponge,kukrimate/Glowstone,Tonodus/WaterGleam,GreenBeard/GlowstonePlusPlus,jimmikaelkael/GlowstonePlusPlus,BlazePowered/Blaze-Server,kukrimate/Glowstone,GlowstoneMC/GlowstonePlusPlus,LukBukkit/GlowstonePlusPlus,BlazePowered/Blaze-Server,jimmikaelkael/GlowstonePlusPlus