Create a phase, lending limit and multiple allocations together

A new form for creating phases, along with lending limits and assigning them to lenders along with an allocation.

Adds a new resource `/phases_with_lending_limits` and new presenters `PhaseWithLendingLimit` and the snappily named `LenderLendingLimit` for validating and creating `Phase` and `LendingLimit` from the form.

![Screen Shot 2013-02-20 at 16 33 16](https://f.cloud.github.com/assets/35913/176673/8046af2c-7b7b-11e2-9f48-dc2292f3936a.png)