[howTo] Improve piaware results

I noticed I've got drastically better results with piaware ( Raspberry Pi + Flight Aware ADS-B ) by enabling SSH, and upgrading the underlying raspbian packages.

Enable ssh on raspbian:

• Mount the micro-sd on another computer. 
• Create an empty file called "ssh" 
• Boot the Pi
• sudo apt-get update; sudo apt-get upgrade

Alternatively you can go through flightware and issue an "Upgrade all installed Debian Packages" command. 

My results went from: 18k reports to 50k reports (Fri vs Fri comparison). With no change to antenna placement or hardware. 

Dramatic difference. Pretty obvious when the change was made.