Adds landing page and a few bug fixes and follow using ajax

Merge branch 'follow-ajax' into 'master'

Make Follow button ajax

See merge request TeamSPD/Chirp!106

Provides better search results, mobile improvements, and few bug fixes.

- Now, post add works on mobile.
- Navbar collapse work great on mobile
- Dropdown on navbar with profile photo hides on collapse
- Fix text bleed on post
- Linkify links on post
- Improve @mention link on frontend
- Fix issue with search on mobile
- Fix share button color change on share
- Show character counter budget on post add modal
- Show trends and follow suggestions on empty search result

Rereleasing v0.8.5 as v0.9.0.

Prerelease for beta release v0.9.0