Expose lyric.ticks() to plugin framework

Midi import works great for the most part, but I came across a file that had hyphens and underscores attached to lyrics. I wanted to convert these to syllabic and melismatic lyrics, so I tried to write a plugin. Unfortunately, only the syllabic property is exposed; I concluded that I needed access to the ticks property to programmatically add melismas.

After adding the one line to the code, I was able to create the plugin. I'd like to add this change for all to benefit.