Fix marginal ticks example (closes #641
Fix marginal ticks example (closes #641

oesteban/seaborn,drewokane/seaborn,olgabot/seaborn,mia1rab/seaborn,phobson/seaborn,lukauskas/seaborn,uhjish/seaborn,anntzer/seaborn,arokem/seaborn,phobson/seaborn,petebachant/seaborn,nileracecrew/seaborn,muku42/seaborn,lukauskas/seaborn,JWarmenhoven/seaborn,dimarkov/seaborn,bsipocz/seaborn,anntzer/seaborn,clarkfitzg/seaborn,jat255/seaborn,tim777z/seaborn,Lx37/seaborn,huongttlan/seaborn,mwaskom/seaborn,mwaskom/seaborn,arokem/seaborn,wrobstory/seaborn,q1ang/seaborn,mclevey/seaborn,ashhher3/seaborn,sauliusl/seaborn,sinhrks/seaborn,gef756/seaborn,lypzln/seaborn,dhimmel/seaborn