Song Scrolling Improvements

I have implemented a few improvements to the scrolling of songs.

• When you click on Scroll the site will make far better use of the screen size to maximise the scrolling window.
• If you click on Hide (chords diagrams) the space is expanded to cover the chord line as well.
• If you drift your mouse into the scrolling window and in doing so Pause the scroll then a message will let you know the reason for the Pause.
• When the scroll comes to an end it keeps scrolling for a few lines. This is useful for when you are projecting the song to a screen and allows those at the back to see over the heads of the front people to the end of the song!
• When you click on Stop the page will reset to the default

I hope these are useful