fixed negative clip.start calculation on SequenceManager.from_seq()
fixed negative clip.start calculation on SequenceManager.from_seq()

sergeneren/anima,sergeneren/anima,eoyilmaz/anima,sergeneren/anima,eoyilmaz/anima,eoyilmaz/anima,eoyilmaz/anima,eoyilmaz/anima