初步实现滚动显示歌词，并且在单行内逐渐变色。
#	modified:   res/layout/activity_lrc_test.xml
#	modified:   src/com/example/lrctest/LrcTest.java
#	modified:   src/com/example/lrctest/LrcView.java
#	new file:   src/com/example/lrctest/VerticalScrollTextView.java
#