Create libraries based on external unmanaged directories (#147)

* Library management is now complete

* Library functions complete

* Added default platform support

gaseous-tools/Database/MySQL/gaseous-1004.sql

@@ -0,0 +1,11 @@
+CREATE TABLE `GameLibraries` (
+  `Id` int NOT NULL AUTO_INCREMENT,
+  `Name` VARCHAR(255) NOT NULL,
+  `Path` longtext NOT NULL,
+  `DefaultLibrary` int NOT NULL DEFAULT '0',
+  `DefaultPlatform` bigint NOT NULL DEFAULT '0',
+  PRIMARY KEY (`Id`)
+);
+
+ALTER TABLE `Games_Roms` 
+ADD COLUMN `LibraryId` INT NULL DEFAULT 0 AFTER `MetadataVersion`;