Merge pull request #9 from tanxuewei/master

modify fast-backward and backward
update some icons
update some icons
update less/Xicon.less file
Merge pull request #10 from xinhuarao/master

add align-left,align-right, search and cloud icons
Merge branch 'tanxuewei-master'
modifiy mail & merge align-right,search
modifiy mail & merge align-right,search
Merge pull request #12 from colorpeach/master

modifiy mail & merge align-right,search