Move all core files into src/core.

Move Browser & Node specs to test against lib/jasmine.js instead of the separate source. Yes, this makes development a little harder but it's better to test that jasmine.js was built correctly.

src/core/Block.js

@@ -0,0 +1,22 @@
+/**
+ * Blocks are functions with executable code that make up a spec.
+ *
+ * @constructor
+ * @param {jasmine.Env} env
+ * @param {Function} func
+ * @param {jasmine.Spec} spec
+ */
+jasmine.Block = function(env, func, spec) {
+  this.env = env;
+  this.func = func;
+  this.spec = spec;
+};
+
+jasmine.Block.prototype.execute = function(onComplete) {  
+  try {
+    this.func.apply(this.spec);
+  } catch (e) {
+    this.spec.fail(e);
+  }
+  onComplete();
+};