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/SuiteSpec.js

@@ -138,7 +138,7 @@ describe('Suite', function() {
 
     expect(function() {
       suite.addExpectationResult(false, { message: 'failed' });
-    }).toThrowError(jasmineUnderTest.private.errors.ExpectationFailed);
+    }).toThrowError(privateUnderTest.errors.ExpectationFailed);
 
     expect(suite.doneEvent().status).toBe('failed');
     expect(suite.doneEvent().failedExpectations).toEqual([
@@ -149,9 +149,7 @@ describe('Suite', function() {
   it('does not add an additional failure when an expectation fails', function() {
     const suite = new privateUnderTest.Suite({});
 
-    suite.handleException(
-      new jasmineUnderTest.private.errors.ExpectationFailed()
-    );
+    suite.handleException(new privateUnderTest.errors.ExpectationFailed());
 
     expect(suite.doneEvent().failedExpectations).toEqual([]);
   });