Fixed focus issues.
Fixed panel size for retina.
Use line spacing setting.
Shortcuts for Copy/Paste/New session
Don't send data on right mouse button events.
Fixed key events handling.
Make Copy & Paste methods protected
Fix bug when scrolling in the scroll buffer

When scrolling down, if the new bottom line is shorter than the previous
one, then the tail of the previous bottom line is not cleared.
Merge pull request #19 from Plonk42/copy_paste_protected

Make Copy & Paste methods protected
Merge pull request #20 from Plonk42/scroll_clear_bug

Fix bug when scrolling in the scroll buffer
Merge remote-tracking branch 'origin/master'
Fixed lines buffer manipulation on scrolling.
Cleanup.