Updating to markdown-mode 2.0

http://jblevins.org/projects/markdown-mode/
Adding Projectile and dependencies
Merge pull request #11 from swaroopch/feature/markdownmode20

Updating to markdown-mode 2.0
Merge pull request #12 from swaroopch/feature/projectile

Adding Projectile and dependencies. Also add flx-ido for better fuzzy matching inside ido.
Fixing typo
Merge pull request #13 from swaroopch/patch-1

Fixing typo.
Adding scroll-margin setting
Merge pull request #14 from swaroopch/feature/margin

Adding scroll-margin setting
Save projectile bookmarks in etc dir.