add help page

This is a draft of a new help page:
![faq_getting_help](https://f.cloud.github.com/assets/3798614/979007/da5fb5ca-06d2-11e3-89b1-168dc4416b77.png)
![faq_aspects](https://f.cloud.github.com/assets/3798614/979008/de7ba4f2-06d2-11e3-9628-5af1b5cdd9ac.png)
![faq_sharing](https://f.cloud.github.com/assets/3798614/979009/e11b87d6-06d2-11e3-9e78-74e00ac7954b.png)


[loomio discussion](https://www.loomio.org/discussions/5347)