Implemented exporting symbol fonts;

Rendering symbols to an image always uses anti-aliassing (by downsampling from a large size);
Finished the spoiler export template;
Added <soft-line> tag to make line breaks use the line height for soft line breaks

git-svn-id: svn://svn.code.sf.net/p/magicseteditor/code/trunk@440 0fc631ac-6414-0410-93d0-97cfa31319b6

src/data/export_template.hpp

@@ -48,6 +48,7 @@ struct ExportInfo {
 	String          directory_relative; ///< The directory for storing extra files (or "" if !export->create_directory)
 	                                    ///  This is just the directory name
 	String          directory_absolute; ///< The absolute path of the directory
+	set<String>     exported_images;	///< Images (from symbol font) already exported
 };
 
 DECLARE_DYNAMIC_ARG(ExportInfo*, export_info);