Rework copy on policies#new

Reworking of the copy on the policy creation page to simplify it. Based on initial drafts by @Video-drome at the hackfest. I did a bit of layout work at the same time and moved the tips behind a disclosure button.

After:
![screen shot 2014-10-11 at 5 58 59 pm](https://cloud.githubusercontent.com/assets/1239550/4601752/a7c1e7e0-5114-11e4-81a9-9dd1cae93bcb.png)

Before:
![screen shot 2014-10-11 at 5 58 41 pm](https://cloud.githubusercontent.com/assets/1239550/4601750/99203a5c-5114-11e4-974d-8ee79013a442.png)

closes #396 
>...since our records begin

Reads awkwardly to me. Just making it past tense doesn't seem to fix it either. Maybe we need to rework the sentence.