Optimized arguments parsing for fire() chain.

1. Avoid slice/iteration for common signatures - fire("foo") and fire("foo", {})

2. Add private _fire(arr) to avoid reconverting arguments to array from et.fire() -> ce.fire()

3. Fixed one rare path, where we were passing the raw `arguments` to use by reference in
   _monitor.

Big boost for Chrome, smaller boost for others, although still better than the original (see fire
related tests below).

NOTES:

a. The publish number variance is unrelated. Nothing in this code change touches publish
b. The benchmark tests have been changed as of this commit. I realized a couple of my
tests were using the same EventTarget for each iteration which was either bogging stuff done
(e.g. publishing a gazillion events), or resulting in less work than expected (e.g. publishing
and already published event instead of a fresh publish).

Testing
-------

All tests pass, except for known yogi test/io test failure (fails prior to this change also and in clean dev-3.x)

[Total]: Passed: 10725 Failed: 1 Total: 10811 (ignored 85) (8 minutes, 26 seconds)

[io-base Test Suite]: Passed: 39 Failed: 1 Total: 40 (ignored 0) (1.372 seconds)
    testPOSTWithNoData
       Values should be the same.
       Expected: 200 (number)
       Actual: 204 (number)

Numbers
-------

This commit:

Chrome 25

new BaseCore() x 58,060
new Base() x 24,375
Subscribe + Fire - 10 different events x 7,590
Fire - 10 different events, no listeners x 195,272
Publish - 10 different events x 45,946
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 10 listeners x 22,581
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 2 listeners x 63,541
EventTarget Construction + Publish(foo) + Fire(foo) - no listeners x 243,016
Fire With Payload - 10 listeners x 267,247
Fire - 10 listeners x 312,207
Fire With Payload - 2 listeners x 307,782
Fire - 2 listeners x 511,529
Publish x 416,336

FF 19

new BaseCore() x 23,653
new Base() x 10,278
Subscribe + Fire - 10 different events x 3,248
Fire - 10 different events, no listeners x 72,554
Publish - 10 different events x 20,867
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 10 listeners x 11,214
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 2 listeners x 26,821
EventTarget Construction + Publish(foo) + Fire(foo) - no listeners x 77,164
Fire With Payload - 10 listeners x 80,366
Fire - 10 listeners x 87,933
Fire With Payload - 2 listeners x 101,368
Fire - 2 listeners x 111,964
Publish x 180,157

Safari 6

new BaseCore() x 58,440
new Base() x 20,653
Subscribe + Fire - 10 different events x 5,137
Fire - 10 different events, no listeners x 144,626
Publish - 10 different events x 51,600
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 10 listeners x 16,081
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 2 listeners x 41,634
EventTarget Construction + Publish(foo) + Fire(foo) - no listeners x 151,295
Fire With Payload - 10 listeners x 84,037
Fire - 10 listeners x 82,022
Fire With Payload - 2 listeners x 153,113
Fire - 2 listeners x 154,749
Publish x 487,979

Prior commit:

Chrome 25

new BaseCore() x 58,222
new Base() x 20,923
Subscribe + Fire - 10 different events x 6,923
Fire - 10 different events, no listeners x 74,543
Publish - 10 different events x 46,005
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 10 listeners x 22,479
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 2 listeners x 58,373
EventTarget Construction + Publish(foo) + Fire(foo) - no listeners x 171,370
Fire With Payload - 10 listeners x 161,504
Fire - 10 listeners x 203,838
Fire With Payload - 2 listeners x 217,060
Fire - 2 listeners x 265,981
Publish x 394,612

FF 19

new BaseCore() x 23,768
new Base() x 9,561
Subscribe + Fire - 10 different events x 3,150
Fire - 10 different events, no listeners x 70,747
Publish - 10 different events x 21,088
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 10 listeners x 10,909
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 2 listeners x 26,416
EventTarget Construction + Publish(foo) + Fire(foo) - no listeners x 72,134
Fire With Payload - 10 listeners x 75,308
Fire - 10 listeners x 79,160
Fire With Payload - 2 listeners x 94,831
Fire - 2 listeners x 101,513
Publish x 180,391

Safari 6

new BaseCore() x 59,982
new Base() x 20,276
Subscribe + Fire - 10 different events x 4,813
Fire - 10 different events, no listeners x 102,961
Publish - 10 different events x 53,298
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 10 listeners x 16,253
EventTarget Construction + Publish(foo) + Subscribe(foo) + Fire(foo) - 2 listeners x 40,741
EventTarget Construction + Publish(foo) + Fire(foo) - no listeners x 133,001
Fire With Payload - 10 listeners x 83,356
Fire - 10 listeners x 81,567
Fire With Payload - 2 listeners x 129,808
Fire - 2 listeners x 136,671
Publish x 480,559