Added note about a port forwarding alternative - pagekite.

I don't know whether it's worth you including this or not as it's properly outside of scope for your project, but as you're mentioning about inbound connections on a variety of methods, then it might be of interest.
Merge branch 'pr/3'

* pr/3:
  Added note about a port forwarding alternative - pagekite.
Add Hamachi VPN to README
Merge branch 'update-readme'

* update-readme:
  Add Hamachi VPN to README
  Added note about a port forwarding alternative - pagekite.