Redesigned moudule system

* Top level private APIs (e.g. jasmine.private.whatever) are no longer
  exposed
* jasmineRequire is no longer exposed
* core is self-booting
* Globals are automatically created in browsers. (They can subsequently
  be removed by user code if desired.)
* Globals are *not* automatically created in Node. An installGlobals
  function is exported instead. The jasmine package calls installGlobals
  unless configured not to do so.
* In Node, the same instance is returned each time jasmine-core is
  imported. A reset function is exported. It effectively resets all state
  by discarding the env and creating a new one. This allows mulitple
  sequential runs within the same process to be independent of each
  other, but does not allow multiple concurrent runs. (That probably never
  worked anyway.)

Fixes #2094

scripts/runSpecsInNode.js

@@ -1,8 +1,9 @@
-verifyNoGlobals(() => require('../lib/jasmine-core.js').noGlobals());
+let jasmineCore;
+verifyNoGlobals(() => { jasmineCore = require('../lib/jasmine-core.js'); });
+jasmineCore.installGlobals();
 
 const Jasmine = require('jasmine');
-const jasmineCore = require('../lib/jasmine-core.js');
-const runner = new Jasmine({jasmineCore: jasmineCore});
+const runner = new Jasmine({jasmineCore});
 
 runner.loadConfigFile('./spec/support/jasmine.json');
 runner.exitOnCompletion = false;