If branches merged.
Min key length set to 2048.

[#262 state:fixed assigned:mento milestone:1.1.4]
Cancel should be the default button for dangerous operations.
showExpertSettings added.
Only experts can remove/revoke the last self-sig.
Show a message to explain photo Drag & Drop.
Allow drag & drop of JPG, in upper case.
"Mail public key" added to context menu.
"Move sec ring" hidden.