Export diagrams to PNG, JPG and SVG format

I have added to Qucs diagram export to other formats ability. Now by right click on diagram you can acess export to graphics dialog. You can change format and size of result image. Screenshots and example of exported image are attached.
![1](https://f.cloud.github.com/assets/4920080/1558369/ab4e767a-4f86-11e3-9e06-eefd8d49322e.png)

![export-to-graphics-context-mnu](https://f.cloud.github.com/assets/4920080/1558367/8cd89be4-4f86-11e3-801f-3a170ff67ed4.png)
![export-to-graphics-dlg](https://f.cloud.github.com/assets/4920080/1558368/93bbf4ba-4f86-11e3-8ed9-c55610691cca.png)