Merge pull request #1 from yulijia/gh-pages

 rgl.surface() may cause 'segfault' problem in RedHat ( Fedora ) without rgl.open()
rebuild the website by `rake knit`
need a space between 'animations' and 'in'
a grad.desc() function example in animation package
Fix spelling and grammar mistakes
do not need mention default options nmax=50
use {} in function block
use '-' in  code label
change author name and add reviewer
add a author ‘yulijia'
set graphical parameters, it can show animation figure main title.