Merge pull request #619 from SatishTalim/master

commit - minor
Update: Jyotiska NK Twitter id change #410
Merge pull request #411 from Qwinix/issue_410

Update: Jyotiska NK Twitter id change #410
Merge pull request #620 from Qwinix/master

Updated: Jyotiska NK Twitter id change #614
Add David Calavera as a Speaker #413
Merge pull request #414 from Qwinix/issue_413

Add David Calavera as a Speaker #413
Merge pull request #623 from Qwinix/master

Added David Calavera as a Speaker #621
commit