Disable window.opener object when using target="_blank"

See merge request !6

See https://www.jitbit.com/alexblog/256-targetblank---the-most-underestimated-vulnerability-ever/ for details.

Add Twitter button to footer

See merge request !5

Add f-droid and twitter badges

Closes #4

See merge request !4

Fix logo home link in press release

See merge request !3

Update website for public beta, add Google Play button

See merge request !2

Conflicts:
	index.html

Conflicts:
	about.html

Add beta press-release

See merge request !1

See http://arstechnica.co.uk/security/2016/12/at-least-10-million-android-users-imperiled-by-popular-airdroid-app/