Implement the main form of operations view

This is a initial implementation of the form corresponding to the operations view. It provides the controls necessary to insert the properties of a exchange and submit it to the broker set.

![captura de pantalla 2014-07-02 a la s 13 48 50](https://cloud.githubusercontent.com/assets/738507/3455630/d4ec7868-01e4-11e4-8736-c1838ffe932e.png)

I have a question about the kind of language we want to use. Do we want the app to feel familiar to people in the financial world or are we targetting the general population? If the financial world is a priority, we should use financial terms like `limit order` instead of saying `custom price`.