Optionally disable projects section and allow custom posts/projects permalinks

[wjh18]

There are currently two limitations with the theme that reduce flexibility for users:

1. The projects section can't be disabled. There may be users who like the theme and only want to use the posts section for blogging.
2. The posts and projects section permalinks are hard-coded throughout the theme (in SEO features, etc.). This means that if someone wants to change posts to blog for example, they would need to override various layout templates in their project repo. This isn't a very good user experience.

It would be helpful to fix these issues ASAP to broaden the appeal of the theme.