Update "tempo" effect documentation. Also fix some punctuation inconsistencies in other parts of the man page.
Update "tempo" effect documentation. Also fix some punctuation inconsistencies in other parts of the man page.

mhartzel/sox_personal_fork,mhartzel/sox_personal_fork,jacksonh/sox,mhartzel/sox_personal_fork,CaptainHayashi/sox,davel/sox,CaptainHayashi/sox,MageSlayer/sox,pcqpcq/sox,davel/sox,MageSlayer/sox,CaptainHayashi/sox,cbagwell/sox,davel/sox,cbagwell/sox,Motiejus/sox,pcqpcq/sox,uklauer/sox,cbagwell/sox,CaptainHayashi/sox,Distrotech/sox,Distrotech/sox,Motiejus/sox,cbagwell/sox,uklauer/sox,MageSlayer/sox,jacksonh/sox,uklauer/sox,pcqpcq/sox,MageSlayer/sox,uklauer/sox,mhartzel/sox_personal_fork,Distrotech/sox,Distrotech/sox,Motiejus/sox,davel/sox,jacksonh/sox,MageSlayer/sox,jacksonh/sox,Motiejus/sox,pcqpcq/sox