change testling firefox min version from 10 to 15

also change testling image to insecure url as an attempt to flush github cache

README.md

@@ -1,7 +1,7 @@
 # bitcoinjs-lib
 
 [![Build Status](https://travis-ci.org/bitcoinjs/bitcoinjs-lib.png)](https://travis-ci.org/bitcoinjs/bitcoinjs-lib)
-[![browser support](https://ci.testling.com/bitcoinjs/bitcoinjs-lib.png)](https://ci.testling.com/bitcoinjs/bitcoinjs-lib)
+[![browser support](http://ci.testling.com/bitcoinjs/bitcoinjs-lib.png)](https://ci.testling.com/bitcoinjs/bitcoinjs-lib)
 
 A pure JavaScript Bitcoin library for node.js and browsers. Backed by (slowly improving) testing, proven by over a million wallet users. The backbone for almost all Bitcoin web wallets in production today.
 

package.json

@@ -24,7 +24,7 @@
     "browsers": [
       "ie/8..latest",
       "chrome/20..latest",
-      "firefox/10..latest",
+      "firefox/15..latest",
       "safari/latest",
       "opera/11.0..latest",
       "iphone/6",