Updated Pushbullet to use PB API v2, and added PB as a URL sharing service

Hey there Jaex, hope you're doing well :D.

I've learned a bunch more about SourceTree and git in general since we last spoke (and I used what you showed me to add support for the API v2).

It took me a while, but I finally got it done (and made some improvements along the way).

Hope you like them :-).

~Karl