Split boot.js in two to allow the env to be configured in between

This is mainly intended to support jasmine-browser-runner, which will load
a script that configures the env in between the two boot files (boot0.js and
boot1.js). The single-file boot.js is retained for now but will be removed
in a future release.

src/core/Env.js

@@ -170,35 +170,28 @@ getJasmineRequireObj().Env = function(j$) {
      * @function
      */
     this.configure = function(configuration) {
+      var booleanProps = [
+        'random',
+        'failFast',
+        'failSpecWithNoExpectations',
+        'oneFailurePerSpec',
+        'hideDisabled'
+      ];
+
+      booleanProps.forEach(function(prop) {
+        if (typeof configuration[prop] !== 'undefined') {
+          config[prop] = !!configuration[prop];
+        }
+      });
+
       if (configuration.specFilter) {
         config.specFilter = configuration.specFilter;
       }
 
-      if (configuration.hasOwnProperty('random')) {
-        config.random = !!configuration.random;
-      }
-
-      if (configuration.hasOwnProperty('seed')) {
+      if (typeof configuration.seed !== 'undefined') {
         config.seed = configuration.seed;
       }
 
-      if (configuration.hasOwnProperty('failFast')) {
-        config.failFast = configuration.failFast;
-      }
-
-      if (configuration.hasOwnProperty('failSpecWithNoExpectations')) {
-        config.failSpecWithNoExpectations =
-          configuration.failSpecWithNoExpectations;
-      }
-
-      if (configuration.hasOwnProperty('oneFailurePerSpec')) {
-        config.oneFailurePerSpec = configuration.oneFailurePerSpec;
-      }
-
-      if (configuration.hasOwnProperty('hideDisabled')) {
-        config.hideDisabled = configuration.hideDisabled;
-      }
-
       // Don't use hasOwnProperty to check for Promise existence because Promise
       // can be initialized to undefined, either explicitly or by using the
       // object returned from Env#configuration. In particular, Karma does this.