add support for conjunctions with bounding box

Allow `with().in_bounding_box()` restrictions to be added to conjunctions
such as `any_of`, e.g.

    Model.search do
      any_of do
        with(:city, city)
        with(:location).in_bounding_box(se, nw)
      end
    end

sunspot/lib/sunspot/query/bbox.rb

@@ -5,8 +5,12 @@ def initialize(field, first_corner, second_corner)
         @field, @first_corner, @second_corner = field, first_corner, second_corner
       end
 
+      def to_solr_conditional
+        "[#{@first_corner.join(",")} TO #{@second_corner.join(",")}]"
+      end
+
       def to_params
-        filter = "#{@field.indexed_name}:[#{@first_corner.join(",")} TO #{@second_corner.join(",")}]"
+        filter = "#{@field.indexed_name}:#{to_solr_conditional}"
 
         {:fq => filter}
       end

sunspot/lib/sunspot/query/restriction.rb

@@ -169,6 +169,17 @@ def to_positive_boolean_phrase
           end
       end
 
+      class InBoundingBox < Base
+        def initialize(negated, field, first_corner, second_corner)
+          @bbox = Sunspot::Query::Bbox.new(field, first_corner, second_corner)
+          super negated, field, [first_corner, second_corner]
+        end
+
+        def to_solr_conditional
+          @bbox.to_solr_conditional
+        end
+      end
+
       # 
       # Results must have field with value equal to given value. If the value
       # is nil, results must have no value for the given field.

sunspot/spec/api/query/connectives_examples.rb

@@ -198,4 +198,16 @@
       :fq, '(_query_:"{!geofilt sfield=coordinates_new_ll pt=23,-46 d=100}" OR _query_:"{!geofilt sfield=coordinates_new_ll pt=42,56 d=50}")'
     )
   end
+
+  it 'creates a conjunction of in_bounding_box queries' do
+    search do
+      any_of do
+        with(:coordinates_new).in_bounding_box([23, -46], [25, -44])
+        with(:coordinates_new).in_bounding_box([42, 56], [43, 58])
+      end
+    end
+    connection.should have_last_search_including(
+      :fq, '(coordinates_new_ll:[23,-46 TO 25,-44] OR coordinates_new_ll:[42,56 TO 43,58])'
+    )
+  end
 end

sunspot/spec/integration/geospatial_spec.rb

@@ -26,7 +26,7 @@
       results.should_not include(@post)
     end
 
-    it "allows conjunction queries" do
+    it "allows conjunction queries with radius" do
       results = Sunspot.search(Post) {
         any_of do
           with(:coordinates_new).in_radius(32, -68, 1)
@@ -36,6 +36,17 @@
 
       results.should include(@post)
     end
+
+    it "allows conjunction queries with bounding box" do
+      results = Sunspot.search(Post) {
+        any_of do
+          with(:coordinates_new).in_bounding_box([31, -69], [33, -67])
+          with(:coordinates_new).in_bounding_box([35, 68], [36, 69])
+        end
+      }.results
+
+      results.should include(@post)
+    end
   end
 
   describe "filtering by bounding box" do