Fixes #976 Now uses GitHub to retrieve most current version

Reworked whole Version Checker with an extensible interface to add any other service later on easier.
The version checker now has its own config file, to collect the different options and extract them from the main config file.
In that you can specify how fine the versions should be checked.

src/main/java/appeng/core/FacadeConfig.java

@@ -35,8 +35,8 @@ public class FacadeConfig extends Configuration
 	public static FacadeConfig instance;
 	final Pattern replacementPattern;
 
-	public FacadeConfig(String path) {
-		super( new File( path + "Facades.cfg" ) );
+	public FacadeConfig( File facadeFile ) {
+		super( facadeFile );
 		this.replacementPattern = Pattern.compile( "[^a-zA-Z0-9]" );
 	}