Artist: Update documentation

I add more details and remove this section of the DESIGN file.

Signed-off-by: Anna Schumaker <Anna@OcarinaProject.net>

DESIGN

@@ -120,44 +120,6 @@ Tag Database:
 
 
 
-Artist Tag:
-	The arist tag is used to collect basic information about the various
-	artists that have been added to the library.
-
-- Artist:
-	class Artist : public DatabaseEntry {
-	public:
-		std::string name;
-		std::string lower;
-
-		Artist();
-		Artist(const std::string &);
-		const std::string primary_key() const;
-		void read(File &);
-		void write(File &);
-	};
-
-- File Format:
-	File << name;
-
-- API:
-	Artist();
-		Initialize an invalid Artist instance.
-
-	Artist(const std::string &artist_name);
-		Set artist_name and find the lowercase form.
-
-	const std::string Artist :: primary_key() const;
-		Use artist name as primary key.
-
-	void Artist :: read(File &f);
-		Read artist name from file and find the lowercase form.
-
-	void Artist :: write(File &f);
-		Write artist name to file.
-
-
-
 Album Tag:
 	The album tag is used to collect information about each artist's albums.
 

include/core/tags/artist.h

@@ -8,36 +8,48 @@
 #include <core/database.h>
 
 /**
- * Artist tag
+ * The Artist tag is used to store the name of artists added
+ * to the tag database.
+ *
+ * When writing an Artist tag to disk, only the artist name
+ * needs to be written.
+ *
+ * 	... << name1
+ * 	... << name2
+ * 	... << name3
  */
 class Artist : public DatabaseEntry {
 public:
 	std::string name;	/**< Artist name. */
 	std::string lower;	/**< Artist name (lowercase). */
 
-	/** Artist tag constructor */
-	Artist();
+	Artist(); /**< Artist tag constructor */
 
 	/**
 	 * Artist tag constructor
+	 *
 	 * @param  name  Artist name
 	 */
 	Artist(const std::string &);
 
 	/**
 	 * Called to access the artist tag's primary key
+	 *
 	 * @return Artist::name
 	 */
 	const std::string primary_key() const;
 
 	/**
-	 * Read artist information from file.
+	 * Read the artist name from file and
+	 * find the lowercase form.
+	 *
 	 * @param  file  The file to read from.
 	 */
 	void read(File &);
 
 	/**
-	 * Write artist information to file.
+	 * Write the artist name to file.
+	 *
 	 * @param  file  The file to write to.
 	 */
 	void write(File &);