title: Calculating great-circle distance matrix
body: <p><code>dist(coords)</code> provides the distance matrix using Euclidean distances; it also provides several other options. But it doesn't provide any option such as the haversine formula.</p>
  
  <p><code>distHaversine()</code> calculates the distance I want (great-circle) for given two set of lat/long coordinates. I am wondering if there is an existing package/function that calculates great-circle distance matrix using the haversine formulation.</p>