Pledge Display Enhancement - Listing of a new column for Contribution type

The information on the Pledge tab display is not particularly useful in organizations where donors can pledge to multiple causes, or where pledges are used as a means of tracking regular payments that are owed from an individual or organization.

One of our client needed more descriptive data to be displayed on the pledge listing - "Pledged for:" column consisting of the name of the contribution_type associated with the pledge.

Assuming this would be very useful to community, we submitting the patch.