Stop using URI.escape.

Fixes #609. Bing seems to support this type of character escaping now.
It's not discussed in their documentation but it works with every query
I've tried so hopefully we're finally good on this issue.

Also remove some unnecessary assertions from tests.

lib/geocoder/lookups/bing.rb

@@ -23,7 +23,7 @@ module Geocoder::Lookup
     private # ---------------------------------------------------------------
 
     def base_url(query)
-      text = URI.escape(query.sanitized_text.strip)
+      text = CGI.escape(query.sanitized_text.strip)
       url = "#{protocol}://dev.virtualearth.net/REST/v1/Locations/"
       if query.reverse_geocode?
         url + "#{text}?"

test/unit/lookups/bing_test.rb

@@ -43,7 +43,6 @@ class BingTest < GeocoderTestCase
       :region => "uk"
     ))
     assert_match(%r!Locations/uk/\?q=manchester!, url)
-    assert_no_match(/query/, url)
   end
 
   def test_query_url_without_region
@@ -52,27 +51,24 @@ class BingTest < GeocoderTestCase
       "manchester"
     ))
     assert_match(%r!Locations/\?q=manchester!, url)
-    assert_no_match(/query/, url)
   end
 
-  def test_query_url_contains_address_with_spaces
+  def test_query_url_escapes_spaces_in_address
     lookup = Geocoder::Lookup::Bing.new
     url = lookup.query_url(Geocoder::Query.new(
       "manchester, lancashire",
       :region => "uk"
     ))
-    assert_match(%r!Locations/uk/\?q=manchester,%20lancashire!, url)
-    assert_no_match(/query/, url)
+    assert_match(%r!Locations/uk/\?q=manchester%2C\+lancashire!, url)
   end
 
-  def test_query_url_contains_address_with_trailing_and_leading_spaces
+  def test_query_url_strips_trailing_and_leading_spaces
     lookup = Geocoder::Lookup::Bing.new
     url = lookup.query_url(Geocoder::Query.new(
       " manchester, lancashire ",
       :region => "uk"
     ))
-    assert_match(%r!Locations/uk/\?q=manchester,%20lancashire!, url)
-    assert_no_match(/query/, url)
+    assert_match(%r!Locations/uk/\?q=manchester%2C\+lancashire!, url)
   end
 
   def test_raises_exception_when_service_unavailable