Fixed #990 Removed mentions of geolocation from settings page

Closes https://openhatch.org/bugs/issue990. 

Deleted code in the settings page that has any mention of geolocation,
including location-related html on settings page, views, and tests.

Changed default url link "settings" on header from
/settings/location/ to /settings/invite_someone.

Made design decision to re-structure left-hand navigation bar on
settings page in order to improve UI:
    "Tell friend about OpenHatch" tab appears first on top left,
    followed by the "Widgetize yourself" tab, and finally,
    the "Email", "Name", and "Password" navigation tabs.

BEFORE:
![ugly_settings_page](https://cloud.githubusercontent.com/assets/954858/2955056/2df66a22-da7b-11e3-96b4-bab43392369c.png)

AFTER:
![990-new-nav-bar](https://cloud.githubusercontent.com/assets/954858/2955047/0716a7dc-da7b-11e3-887d-44106fcc8a12.png)