created base export dialog

i created a own dialog for the export option.

You can choose a icon for the exported executable.
Choose the type of export and can export the first option else messagebox.

This option should still work.
How to make this dialog looks nice, thats still something i dont know.

I also didnt get it, how to tell the export script that the selected icon should be used.
So its really bare form. May you can optimize it a bit further @tommycli ?

![unbenannt-1](https://cloud.githubusercontent.com/assets/342368/4967847/ec529c54-6827-11e4-91a0-d8d719658e43.png)