Add icon : Arc with center

```

"arc icon for edit" can not change the location of the center.

Code for new arc edit icon 

\draw (0:0) ++(45:2) arc (45:-45:2);

Here (0:0) is the center.

Now we can edit the center 

Ref: 
http://tex.stackexchange.com/questions/66490/drawing-a-tikz-arc-specifying-the-c
enter


```

Original issue reported on code.google.com by `a.sivas...@gmail.com` on 9 May 2014 at 5:00
