a grad.desc() function example in animation package
Fix spelling and grammar mistakes
do not need mention default options nmax=50
use '-' in  code label
change author name and add reviewer
add a author ‘yulijia'
set graphical parameters, they are only necessary to set on website.
do not need this annotation
need a space between 'animations' and 'in'
Merge pull request #2 from yulijia/gh-pages

a new post and some update