Add "Started by:" and "Created on: " columns to proposals table

## New columns:
1) "Started by:" - address
2) "Created on: " - date/time

<img width="1117" alt="screen shot 2018-10-27 at 10 14 10" src="https://user-images.githubusercontent.com/1623033/47601465-442d1e80-d9d1-11e8-8c71-45cae6837fd7.png">