Added optimat tradeoff curve example

Some notes:

- I can't multiply a norm by a parameter on the left in the objective: lambda * norm() doesn't work, whereas norm()*lambda does
- Matrices I presume must be dense in the objective? It didn't like sparse ones
- For some reason using logspace(-10,10,n) for the lambdas resulting in infeasibility, so I switched to linspace which produces slightly different results from the matlab reference

I have a handful of other examples in the works, but they all have bugs! Trying to resolve them soon.