Issue #428: search error 131 with small ordinate (< 0.001) + some radius

succeeds:
http://search.twitter.com/search.json?geocode=0.001%2C0.001%2C1km
http://search.twitter.com/search.json?geocode=0.00099999%2C0.00099999

fails with 131:
http://search.twitter.com/search.json?geocode=0.00099999%2C0.001%2C1km
http://search.twitter.com/search.json?geocode=0.001%2C0.00099999%2C1km

i currently use an inconvenient workaround but this is definitely not ideal for our use case