Created tests using Assert API of Chai.js to be able to run tests on all browsers including IE8

with reference to https://github.com/baconjs/bacon.js/issues/426
Without providing second parameter to splice in [this line](https://github.com/vikikamath/bacon.js/blob/master/spec/TickScheduler.coffee#L26) , IE8 gets stuck in indefinite loop.

** NOTES **
* IE8 is not supported by `chai.js` To be able to run `Bacon` tests in `IE8`, it was required to convert tests written in `Expect` API to `Assert` API. 
* I have used [assertive-chai](https://www.npmjs.org/package/assertive-chai) which is `Chai.js` without `Expect` or `Should`
* This pull request allows to create a parallel set of Specs that can be run in IE 8 in addition to modern browsers.

** ISSUES **
IE 8 tests throw 2 types of errors:
* Test utilizes  Object.defineProperty on [this line](https://github.com/vikikamath/bacon.js/blob/master/spec%2FBaconSpec.coffee#L132) ,which IE8 only supports on DOM elements 
* [Probably a bug in sinon API](https://github.com/vikikamath/bacon.js/blob/master/browsertest%2Fjquery-tests.coffee#L15). More investigation required.

Please feel free to use this pull-request as appropriate