#303 #298 #307 #271 and other Fixes

- #303 - Remove Twitter widgets and Organised by text
- #298 - AirBnB as Accommodation Partner
- #307 - Add Speaker Martin Schoch
- #271 - Talk Schedule Page
- Improved the UI of staff information and code of conduct - it now matches the user images with the one we use to display volunteers, workshop participants and speakers.
- Added **Book AirBnB** link to menu which will now points to https://www.airbnb.co.in/events/gopherconindia.  we will change the url if its different