Update README.md

Update Android Studio version
minor tweak in message deleting
Merge remote-tracking branch 'upstream/master'
Merge pull request #214 from sudden6/master

German translation update
Merge pull request #213 from Ansa89/patch-1

Update README.md
changes in deleting specific messages
Merge pull request #216 from strider29/master

changes in deleting specific messages
More robust schedule task executor
Merge branch 'master' of https://github.com/Astonex/Antox
Add Polish translation
Add SG Note 1 wiht PA to working devices
Show text instead of hint for AddFriend button.
Remove hint from the button.
Merge branch 'sdevice' of https://github.com/zetok/Antox into zetok-sdevice
Merge branch 'master' of https://github.com/Corly/Antox into Corly-master
Merge branch 'Corly-master'
Made the keyboard do not show after users reopens the app.
Merge branch 'master' of https://github.com/Corly/Antox into Corly-master
Merge branch 'Corly-master'
Refactoring. Replace all the toxSingleton.db with AntoxDB.