fixed tab icons

The tab icons will now scale appropriately for different iOS devices;
better support for older and smaller devices

Author: rohitdatta

HackTX/Images.xcassets/announcements-filled.imageset/Contents.json

@@ -3,12 +3,12 @@
     {
       "idiom" : "universal",
       "scale" : "1x",
-      "filename" : "Megaphone Filled-64-1.png"
+      "filename" : "Megaphone Filled-64-2-2.png"
     },
     {
       "idiom" : "universal",
       "scale" : "2x",
-      "filename" : "Megaphone Filled-64.png"
+      "filename" : "Megaphone Filled-64-2-1.png"
     },
     {
       "idiom" : "universal",

HackTX/Images.xcassets/announcements-filled.imageset/Megaphone Filled-64-1.png

@@ -3,17 +3,17 @@
     {
       "idiom" : "universal",
       "scale" : "1x",
-      "filename" : "Megaphone-64-1.png"
+      "filename" : "Megaphone-64-2-1.png"
     },
     {
       "idiom" : "universal",
       "scale" : "2x",
-      "filename" : "Megaphone-64.png"
+      "filename" : "Megaphone-64-2.png"
     },
     {
       "idiom" : "universal",
       "scale" : "3x",
-      "filename" : "Megaphone-64-2.png"
+      "filename" : "Megaphone-64-3.png"
     }
   ],
   "info" : {