Made properties editable via gradle.properties

- There should be little incentive to touch `build.gradle`other than adding extra deps

build.gradle

@@ -2,52 +2,90 @@ buildscript {
     repositories {
         jcenter()
         maven { 
-			url = "https://files.minecraftforge.net/maven" 
+			url = 'https://files.minecraftforge.net/maven' 
+		}
+		maven { 
+			url = 'https://repo.spongepowered.org/maven' 
 		}
     }
     dependencies {
         classpath 'net.minecraftforge.gradle:ForgeGradle:2.3-SNAPSHOT'
+		if (project.use_mixins) {
+			classpath 'org.spongepowered:mixingradle:0.6-SNAPSHOT'
+		}
     }
 }
+
 apply plugin: 'net.minecraftforge.gradle.forge'
 
-version = "1.0"
-group = "io.github.cleanroommc.modid" // http://maven.apache.org/guides/mini/guide-naming-conventions.html
-archivesBaseName = "modid"
+if (project.use_mixins) {
+	apply plugin: 'org.spongepowered.mixin'
+}
+
+version = project.mod_version
+group = project.maven_group
+archivesBaseName = project.archives_base_name
 
 sourceCompatibility = targetCompatibility = '1.8'
+
 compileJava {
     sourceCompatibility = targetCompatibility = '1.8'
 }
 
+configurations {
+    embed
+    implementation.extendsFrom(embed)
+}
+
 minecraft {
-    version = "1.12.2-14.23.5.2847"
-    runDir = "run"
-    
-    // the mappings can be changed at any time, and must be in the following format.
-    // snapshot_YYYYMMDD   snapshot are built nightly.
-    // stable_#            stables are built at the discretion of the MCP team.
-    // Use non-default mappings at your own risk. they may not always work.
-    // simply re-run your setup task after changing the mappings to update your workspace.
-    mappings = "stable_39"
-    // makeObfSourceJar = false // an Srg named sources jar is made by default. uncomment this to disable.
+    version = '1.12.2-14.23.5.2847'
+    runDir = 'run'
+    mappings = 'stable_39'
+}
+
+repositories {
+	maven {
+		url 'https://jitpack.io'
+	}
+    maven {
+        url 'https://repo.spongepowered.org/maven'
+    }
 }
 
 dependencies {
 
-	// Remove below comments if you want to an API to download external assets from
-	// deobfCompile ("com.github.CleanroomMC:AssetMover:0.2")
+	if (project.use_assetmover) {
+		deobfCompile ('com.github.CleanroomMC:AssetMover:0.2')
+	}
+	if (project.use_mixins) {
+		embed ('org.spongepowered:mixin:0.8.3') {
+			exclude module: 'asm-commons'
+			exclude module: 'asm-tree'
+			exclude module: 'launchwrapper'
+			exclude module: 'guava'
+			exclude module: 'log4j-core'
+			exclude module: 'gson'
+			exclude module: 'commons-io'
+		}
+		annotationProcessor 'org.spongepowered:mixin:0.8.3:processor'
+    }
+}
+
+sourceSets {
+
+    main {
+        ext.refMap = 'mixins.' + archives_base_name + '.refmap.json'
+    }
 
 }
 
 processResources {
     // this will ensure that this task is redone when the versions change.
-    inputs.property "version", project.version
-    inputs.property "mcversion", project.minecraft.version
+    inputs.property 'version', project.version
+    inputs.property 'mcversion', project.minecraft.version
     // replace stuff in mcmod.info, nothing else
     from(sourceSets.main.resources.srcDirs) {
         include 'mcmod.info'
-                
         // replace version and mcversion
         expand 'version':project.version, 'mcversion':project.minecraft.version
     }
@@ -55,4 +93,23 @@ processResources {
     from(sourceSets.main.resources.srcDirs) {
         exclude 'mcmod.info'
     }
+	rename '(.+_at.cfg)', 'META-INF/$1' // Access Transformers
+}
+
+jar {
+    manifest {
+		def attribute_map = [:]
+		if (project.use_coremod) {
+			attribute_map['FMLCorePlugin'] = project.coremod_plugin_class_name
+		}
+		if (project.use_mixins) {
+			attribute_map['TweakClass'] = 'org.spongepowered.asm.launch.MixinTweaker'
+		}
+        attributes(attribute_map)
+    }
+	if (project.use_mixins && project.pack_mixins_in_jar) {
+		from (configurations.embed.collect { it.isDirectory() ? it : zipTree(it) }) {
+			exclude 'LICENSE.txt', 'module-info.class', 'META-INF/*'
+		}
+	}  
 }

gradle.properties

@@ -1,3 +1,18 @@
 # Sets default memory used for gradle commands. Can be overridden by user or command line properties.
 # This is required to provide enough memory for the Minecraft decompilation process.
-org.gradle.jvmargs=-Xmx3G
+org.gradle.jvmargs = -Xmx3G
+
+# Mod Information
+mod_version = 1.0
+maven_group = com.cleanroommc
+archives_base_name = modid
+
+# Boilerplate Options
+use_mixins = false
+use_coremod = false
+use_assetmover = false
+
+pack_mixins_in_jar = false
+
+# Coremod Arguments
+coremod_plugin_class_name =