Preserve browser history and humanize anchor title

The scroll animation hijacked the link action and prevented the browser history from being updated (perhaps this was intended?). As a result it breaks the back button and makes it more difficult for the user to link
to specific sections of content.

I also renamed one of the section's anchor tags. https://playbook.cio.gov/#plays seems a bit more aesthetically pleasing than https://playbook.cio.gov/#plays_index_anchor. I'd also consider renaming the id's of the play sections based on their titles (e.g. https://playbook.cio.gov/#1-understand-what-people-need).