bulk delete in feature db
use bulk doc api to insert features into feature cache
adds a way to look up failed WFS GetFeature requests, auto-refresh failed GetFeature docs
add failedGetFeature to cache API doc
significantly improved feature removal, throttled ogr2ogr back to one-at-a-time
entire conversion to GeoJSON through streams
adds a function to convert a single WFS to GeoJSON
doc for convertWfs function
a couple more missing function docs
view function to see how big wfs responses are
Merge pull request #39 from usgin/bulk-api

Feature module improvements. Fix #38