Add "paste event" signal

[ailin-nemui]

several new features to pasting text

• you can preview what you have pasted, in case you forgot
• you can put the paste into your input line instead of sending it
• you can directly pastebin it (with a script: https://anti.teamidiot.de/static/nei/*/Code/Irssi/pastebin.pl)
• /set paste_ignore_first_nl to always insert instead of paste single line

[ailin-nemui]

Idea for paste_ignore_first_nl by @KoffaFI

[ailin-nemui]

found to look good by @ahf