Adds gpsxml-filter-zero-bssid for filtering out crappy bssids
rename since we're going to clean all bad ones
Adds XML output to gpsxml2csv

This makes the name kinda stupid, but I'm going with it for now.
Use new undesirable_node? test
Use a sorted set to try to identify patterns
Version bump to 0.2.0
Add testing output files to gitignore
Regenerate gemspec for version 0.2.0