buildVersion() is still needed for the version dropdown

Revert broken section from 91c89c9

src/app.js

@@ -554,6 +554,14 @@ var run = function () {
   });
 
   $.getJSON('https://ethereum.github.io/solc-bin/bin/list.json').done(function (data) {
+    function buildVersion (build) {
+      if (build.prerelease && build.prerelease.length > 0) {
+        return build.version + '-' + build.prerelease;
+      } else {
+        return build.version;
+      }
+    }
+
     // populate version dropdown with all available compiler versions (descending order)
     $.each(data.builds.slice().reverse(), function (i, build) {
       $('#versionSelector').append(new Option(buildVersion(build), build.path));