Add Ellipse icon

#### Purpose

Add Ellipse icon.

Added icon in UI
![ellipseindynamo](https://cloud.githubusercontent.com/assets/8158551/4959879/202a9af2-66bd-11e4-85ca-7abc7cb2d2ab.PNG)

#### Additional references

[MAGN-5341](http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-5341).

#### Reviewers

@Benglin, please, take a look.