Add pushsafer.com notification service

Add pushsafer.com notification service

![Pushsafer](https://www.pushsafer.com/de/assets/logos/logo.png)
# irssi-pushsafer

Plugin for irssi (a console based IRC client) to send push-notifications using https://www.pushsafer.com.

This allows you to be notified when someone messages/mentions you on IRC,
when you're not online.

# Installation

  1. Add a new application to your pushsafer control panel, note the API key.
  2. cp pushsafer.pl to ~/.irssi/scripts/ and symlink into scripts/autorun if you desire.
  3. touch ~/.irssi/pushsafer_ignores
  4. Within irssi:
    1. /load autorun/pushsafer.pl
    2. /set pushsafer_key "your pushsafer private or alias key"
    3. optional set the following params https://www.pushsafer.com/en/pushapi
    4. /set pushsafer_device "device or device group id"
    5. /set pushsafer_sound "sound number"
    6. /set pushsafer_icon "icon number>
    7. /set pushsafer_vibration "vibration 0-3>
    8. /set pushsafer_url "optional url"
    9. /set pushsafer_u