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/services/version/github/DefaultFormattedRelease.java

@@ -0,0 +1,32 @@
+package appeng.services.version.github;
+
+
+import appeng.services.version.Version;
+
+
+/**
+ * Default template when a {@link FormattedRelease} is needed.
+ */
+public final class DefaultFormattedRelease implements FormattedRelease
+{
+	private final Version version;
+	private final String changelog;
+
+	public DefaultFormattedRelease( Version version, String changelog )
+	{
+		this.version = version;
+		this.changelog = changelog;
+	}
+
+	@Override
+	public String changelog()
+	{
+		return this.changelog;
+	}
+
+	@Override
+	public Version version()
+	{
+		return this.version;
+	}
+}