fixup! Rename OpenSPIM to PicardStage

Signed-off-by: Luke Stuyvenberg <stuyvenberg@wisc.edu>
Centered banner messages in build script

I was feeling ostentatious, so I used some printf magic to center the
banner messsages in the new build script. No, there was no particular
motivation for this; I just think it looks nicer...

Signed-off-by: Luke Stuyvenberg <stuyvenberg@wisc.edu>