Started work on welcome view

The biggest change here is that CSS styles are no longer defined in
index.html. Instead, they are defined on a per-state basis in app.js.
This was due to the fact that there were a large number of (necessary)
conflicting styles between main.css and welcome.css.
Added skeleton welcome screen.
Created endpoints for customer and vendor sign up.

Currently, signing up as a new vendor will null out all of the
vendor/address fields.
Fixed the displaying of locations hours & set up the UI aspects of the vendor profile editing modal
Added an already exists modal and hooked up register drop down.
Added cookie for welcome screen.
Updated content for welcome page.
Added a background image for fun.
Renamed /seller page to /vendor

This makes us more consistent with the /vendor/details page.
Fixing fonts and updating textarea resize behaviour
Added Facebook icons to sign in

This is per the mentor’s request as they wanted more clarification that
Facebook would be used to sign in. I didn’t put an icon on the sign in
button as I figured people would remember once they created an account
that Facebook was used.
Added the ability to post to Facebook

The “Update Social Media” button position/styling is far from final,
but I just wanted to get everything hooked up :).

Note that due to the way Facebook permissions work, social media
posting will only work with test users until we have requested
permission from Facebook to post to users’ walls. (This will have to be
done after deployment)

If you want to test the posting in the meantime, use the following
account:

Email: ywqaujd_rosenthalescu_1412740265@tfbnw.net
Password: asdf
Updated views to only show active vendors.

Forgot about this part of the workflow refactor. Also updated
permission classes on several endpoints, as they were insecure.
Setting vendor.compay_name to name on first creation

By doing this, we can simply display vendor.company_name always in the
profile view.
Added My Account button for customers and vendors

Currently, this does nothing for customers. It should probably also be
a dropdown in the future once we have more user options.
Fixed vendor cards to only display in stock items
Fixed permissions error with editing locations.
Vendor can now edit their profile image.  No pictures are set up yet.  Slight UI tweeks
fixed the product inventory card
small UI changes