Improved & unified deprecation handling

* De-duplication now happens in core, not in reporters. This ensures that
  the console doesn't get flooded.
* Stack traces are opt-out, not opt-in.
* The current runnable is not reported or logged for certain deprecations
  where it's irrelevant.
* HtmlReporter shows stack traces in expandable widgets.
* Env#deprecated and Env#deprecatedOnceWithStack are merged.

src/core/ExpectationResult.js

@@ -16,7 +16,7 @@ getJasmineRequireObj().buildExpectationResult = function(j$) {
     var result = {
       matcherName: options.matcherName,
       message: message(),
-      stack: stack(),
+      stack: options.omitStackTrace ? '' : stack(),
       passed: options.passed
     };