osrm startup helpers added

osrm/lib/set.lua

@@ -0,0 +1,23 @@
+-- Set of items
+-- Fast check for inclusion, but unordered.
+-- 
+-- Instead of having to do:
+-- whitelist = { 'apple'=true, 'cherries'=true, 'melons'=true }
+-- 
+-- you can do:
+-- whitelist = Set { 'apple', 'cherries', 'melons' }
+--
+-- and then use it as:
+-- print( whitelist['cherries'] )     => true
+
+function Set(source)
+  set = {}
+  if source then
+    for i,v in ipairs(source) do
+      set[v] = true
+    end
+  end
+  return set
+end
+
+return Set