[ScreenNetEvaluation]

* Replace hardcoded rainbow effect with UserTier02OrBetterCommand.
 * Added Difficulty and Steps param to UpdateNetEvalStats message. The
   beginning of custom-themable online stuff begins.

[ScreenNetSelectMusic]
 * Started to port SampleMusicPreviewMode from ScreenSelectMusic.
 * Changed MusicWheel metrics to read from OnlineMusicWheel instead.
 * Added section, roulette, and random music (not used yet).
 * Stop the music when reaching a section.

[others]
* some theme file additions

src/ScreenNetSelectMusic.h

@@ -58,6 +58,12 @@ protected:
 	void MusicChanged();
 
 	void TweenOffScreen();
+
+	ThemeMetric<SampleMusicPreviewMode> SAMPLE_MUSIC_PREVIEW_MODE;
+	RString m_sSectionMusicPath;
+	RString m_sRouletteMusicPath;
+	RString m_sRandomMusicPath;
+
 private:
 	MusicWheel m_MusicWheel;