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

spec/core/SpecSpec.js

@@ -278,7 +278,7 @@ describe('Spec', function() {
         spec.addExpectationResult(true, { message: 'passed' });
         expect(function() {
           spec.addExpectationResult(false, { message: 'failed' });
-        }).toThrowError(jasmineUnderTest.private.errors.ExpectationFailed);
+        }).toThrowError(privateUnderTest.errors.ExpectationFailed);
 
         expect(spec.doneEvent().failedExpectations).toEqual([
           jasmine.objectContaining({ message: 'failed' })
@@ -453,9 +453,7 @@ describe('Spec', function() {
         queueableFn: {}
       });
 
-      spec.handleException(
-        new jasmineUnderTest.private.errors.ExpectationFailed()
-      );
+      spec.handleException(new privateUnderTest.errors.ExpectationFailed());
 
       expect(spec.doneEvent().failedExpectations).toEqual([]);
     });