Mantis 8308: update libopenjpeg-dotnet-2-1.5.0-dotnet-1.dylib adding missing 64bit support. Built with the macOS 10.13 SDK on Xcode 9.4.1. Thanks Gavin Hird for providing us this.

bin/OpenMetaverse.dll.config

@@ -1,5 +1,6 @@
 <configuration>
     <dllmap os="osx" dll="openjpeg-dotnet.dll" target="libopenjpeg-dotnet-2-1.5.0-dotnet-1.dylib" />
+    <dllmap os="osx" dll="openjpeg-dotnet-x86_64.dll" target="libopenjpeg-dotnet-2-1.5.0-dotnet-1.dylib" />
     <dllmap os="!windows,osx" cpu="x86-64,ia64" dll="openjpeg-dotnet.dll" target="libopenjpeg-dotnet-2-1.5.0-dotnet-1-x86_64" />
     <dllmap os="!windows,osx" cpu="x86-64,ia64" dll="openjpeg-dotnet-x86_64.dll" target="libopenjpeg-dotnet-2-1.5.0-dotnet-1-x86_64" />
     <dllmap os="!windows,osx" cpu="x86" dll="openjpeg-dotnet.dll" target="libopenjpeg-dotnet-2-1.5.0-dotnet-1-i686" />