first-time user, a couple of questions

[Xavier Noria]

Hi! This is the first time I use LilyPond, thanks for the software and
the documentation, they are really good!

I have transcribed a song by Stevie Wonder:

    https://github.com/fxn/scores/blob/master/stevie-wonder/you-and-i.ly

and have a couple of questions I have not been able to figure out searching:

1. As you see, in the source code I have everything organized by
measure. Is there a way to add lyrics by measure instead of in a
separate chunk? The score would be easier to write and follow if I
could mix them.

2. Whole notes and rests are kind of flushed to the left. It's been
many years since I did music but if I am not mistaken it was customary
to have them centered... is there a way to center them?

Thanks!

Xavier