add keyboard shortcuts to clear and cycle through the clipboard history with notifications displayed on screen
keyboard shortcuts to cycle through the clipboard history; Display clipboard content on the screen when clycling
keyboard shortcuts to cycle through the clipboard history; Display clipboard content on the screen when clycling
added Alt modifier to keyboard shortcuts
added Alt modifier to keyboard shortcuts
added Ctrl modifier to keyboard shortcuts
set indentation level to 4
replaced 'var' with 'let'
replaced 'for..in' loop with the 'some' iterator to cycle though items
renamed 'item' to 'entry'
hide the notification label at startup
updated the notification label style
Merge pull request #5 from odrevet/master

Cycle through history with keyboard