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

src/core/util.js

@@ -1,4 +1,4 @@
-getJasmineRequireObj().util = function(j$) {
+getJasmineRequireObj().util = function(j$, private$) {
   'use strict';
 
   const util = {};
@@ -29,7 +29,7 @@ getJasmineRequireObj().util = function(j$) {
       } else if (str === '[object Date]') {
         return new Date(arg.valueOf());
       } else {
-        return j$.private.util.clone(arg);
+        return private$.util.clone(arg);
       }
     });
   };
@@ -51,7 +51,7 @@ getJasmineRequireObj().util = function(j$) {
   };
 
   function callerFile() {
-    const trace = new j$.private.StackTrace(new Error());
+    const trace = new private$.StackTrace(new Error());
     return trace.frames[1].file;
   }