added coreMod property to the minceraft{} block

closes #90

Author: AbrarSyed

src/main/java/net/minecraftforge/gradle/user/patcherUser/forge/ForgeExtension.java

@@ -20,6 +20,7 @@ public class ForgeExtension extends UserBaseExtension
 {
     protected ForgeVersion forgeJson;
     private String         forgeVersion;
+    private String         coreMod = null;
 
     public ForgeExtension(UserBasePlugin<ForgeExtension> plugin)
     {
@@ -34,7 +35,7 @@ public String getForgeVersion()
     public void setForgeVersion(String forgeVersion)
     {
         checkAndSetVersion(forgeVersion);
-        
+
         TokenReplacer.putReplacement(Constants.REPLACE_MC_VERSION, version);
 
         mcpVersion = MCP_VERSION_MAP.get(version);
@@ -210,4 +211,14 @@ private boolean getFromBuildNumber(Integer num)
             return false;
     }
 
+    public String getCoreMod()
+    {
+        return coreMod;
+    }
+
+    public void setCoreMod(String coreMod)
+    {
+        this.coreMod = coreMod;
+    }
+
 }

src/main/java/net/minecraftforge/gradle/user/patcherUser/forge/ForgePlugin.java

@@ -53,6 +53,11 @@ protected void afterEvaluate()
         {
             JavaPluginConvention javaConv = (JavaPluginConvention) project.getConvention().getPlugins().get("java");
             Jar jarTask = (Jar) project.getTasks().getByName("jar");
+            
+            if (!Strings.isNullOrEmpty(ext.getCoreMod()))
+            {
+                jarTask.getManifest().getAttributes().put("FMLCorePlugin", ext.getCoreMod());
+            }
 
             TaskSingleReobf reobfTask = ((TaskSingleReobf) project.getTasks().getByName(UserConstants.TASK_REOBF));
             reobfTask.setClasspath(javaConv.getSourceSets().getByName("main").getCompileClasspath());
@@ -140,12 +145,24 @@ protected List<String> getServerRunArgs(ForgeExtension ext)
     @Override
     protected List<String> getClientJvmArgs(ForgeExtension ext)
     {
-        return ext.getResolvedClientJvmArgs();
+        List<String> out = ext.getResolvedClientJvmArgs();
+        if (!Strings.isNullOrEmpty(ext.getCoreMod()))
+        {
+            out.add("-Dfml.coreMods.load");
+            out.add(ext.getCoreMod());
+        }
+        return out;
     }
 
     @Override
     protected List<String> getServerJvmArgs(ForgeExtension ext)
     {
-        return ext.getResolvedServerJvmArgs();
+        List<String> out = ext.getResolvedServerJvmArgs();
+        if (!Strings.isNullOrEmpty(ext.getCoreMod()))
+        {
+            out.add("-Dfml.coreMods.load");
+            out.add(ext.getCoreMod());
+        }
+        return out;
     }
 }