reintroduce HTTP GET slider in preferences, but with different defaults

defaulting to LL's default of 8 max requests, made slider selectible to 1-8 concurrent connections

indra/newview/skins/default/xui/en/panel_preferences_graphics1.xml

@@ -967,18 +967,36 @@
 		name="TexturesHTTP"
 		top_pad="3"
 		width="256"/>
+      
+<!-- Max Concurrent HTTP GET requests-->
+      <slider
+      control_name="ImagePipelineUseHTTPFetchMaxRequests"
+      decimal_digits="1"
+      follows="left|top"
+      height="16"
+      increment="1"
+      initial_value="8"
+      label="Max number of concurrent HTTP GET requests"
+      label_width="250"
+      layout="topleft"
+      left="20"
+      max_val="8"
+      min_val="2"
+      name="HTTPFetchMaxRequests"
+      top_pad="5"
+      width="375" />
 
 <!-- New Texture detail 5 is lowest, 0 is highest -->
      <text
       type="string"
       length="1"
-      top_pad="20"
+      top_pad="5"
       follows="top|left"
       height="18"
       width="180"
       word_wrap="true"
       layout="topleft"
-      left="10"
+      left="20"
       name="shadows_label">
         Texture Details Loaded:
       </text>
@@ -987,7 +1005,7 @@
       height="23"
       layout="topleft"
       follows="left|top"
-      left="10"
+      left="20"
       top_pad="0" 
       name="TextureDetail"
       width="150">