updated version of mocha and nock for following projects

Since unit test was failing with following error message:

```
% npm test                                                                                                                                          ~/Projects/bamboo-api:master

> bamboo-api@0.0.2 test /Users/pavlo/Projects/bamboo-api
> mocha


  ․․․․․․․․․․․․․․․․․

  ✖ 6 of 18 tests failed:

  1) bamboo.getLatestSuccessfulBuilNumber returns the latest successful build number:
     TypeError: Cannot read property 'readable' of undefined
      at IncomingMessage._read (http.js:347:18)
      at IncomingMessage.Readable.read (_stream_readable.js:320:10)
      at IncomingMessage.read (http.js:339:15)
      at IncomingMessage.<anonymous> (_stream_readable.js:744:45)
      at IncomingMessage.EventEmitter.emit (events.js:92:17)
      at emitDataEvents (_stream_readable.js:770:10)
      at IncomingMessage.Readable.on (_stream_readable.js:691:5)
      at OverridenClientRequest.<anonymous> (/Users/pavlo/Projects/bamboo-api/node_modules/request/main.js:611:16)
      at OverridenClientRequest.EventEmitter.emit (events.js:95:17)
      at /Users/pavlo/Projects/bamboo-api/node_modules/nock/lib/request_overrider.js:220:11
      at process._tickCallback (node.js:419:13)
      at Function.Module.runMain (module.js:499:11)
      at startup (node.js:119:16)
      at node.js:906:3

  2) bamboo.getBuildStatus returns the build Status:
     TypeError: Cannot read property 'readable' of undefined
      at IncomingMessage._read (http.js:347:18)
      at IncomingMessage.Readable.read (_stream_readable.js:320:10)
      at IncomingMessage.read (http.js:339:15)
      at IncomingMessage.<anonymous> (_stream_readable.js:744:45)
      at IncomingMessage.EventEmitter.emit (events.js:92:17)
      at emitDataEvents (_stream_readable.js:770:10)
      at IncomingMessage.Readable.on (_stream_readable.js:691:5)
      at OverridenClientRequest.<anonymous> (/Users/pavlo/Projects/bamboo-api/node_modules/request/main.js:611:16)
      at OverridenClientRequest.EventEmitter.emit (events.js:95:17)
      at /Users/pavlo/Projects/bamboo-api/node_modules/nock/lib/request_overrider.js:220:11
      at process._tickCallback (node.js:419:13)
      at process._tickFromSpinner (node.js:394:15)

  3) bamboo.getAllPlans returns a list of all plans available:
     TypeError: Cannot read property 'readable' of undefined
      at IncomingMessage._read (http.js:347:18)
      at IncomingMessage.Readable.read (_stream_readable.js:320:10)
      at IncomingMessage.read (http.js:339:15)
      at IncomingMessage.<anonymous> (_stream_readable.js:744:45)
      at IncomingMessage.EventEmitter.emit (events.js:92:17)
      at emitDataEvents (_stream_readable.js:770:10)
      at IncomingMessage.Readable.on (_stream_readable.js:691:5)
      at OverridenClientRequest.<anonymous> (/Users/pavlo/Projects/bamboo-api/node_modules/request/main.js:611:16)
      at OverridenClientRequest.EventEmitter.emit (events.js:95:17)
      at /Users/pavlo/Projects/bamboo-api/node_modules/nock/lib/request_overrider.js:220:11
      at process._tickCallback (node.js:419:13)

  4) bamboo.getLatestSuccessfulBuilNumber returns a msg when the plan doesn't contain any successful build:
     TypeError: Cannot read property 'readable' of undefined
      at IncomingMessage._read (http.js:347:18)
      at IncomingMessage.Readable.read (_stream_readable.js:320:10)
      at IncomingMessage.read (http.js:339:15)
      at IncomingMessage.<anonymous> (_stream_readable.js:744:45)
      at IncomingMessage.EventEmitter.emit (events.js:92:17)
      at emitDataEvents (_stream_readable.js:770:10)
      at IncomingMessage.Readable.on (_stream_readable.js:691:5)
      at OverridenClientRequest.<anonymous> (/Users/pavlo/Projects/bamboo-api/node_modules/request/main.js:611:16)
      at OverridenClientRequest.EventEmitter.emit (events.js:95:17)
      at /Users/pavlo/Projects/bamboo-api/node_modules/nock/lib/request_overrider.js:220:11
      at process._tickCallback (node.js:419:13)

  5) bamboo.getAllPlans returns a string saying that there are no plans:
     TypeError: Cannot read property 'readable' of undefined
      at IncomingMessage._read (http.js:347:18)
      at IncomingMessage.Readable.read (_stream_readable.js:320:10)
      at IncomingMessage.read (http.js:339:15)
      at IncomingMessage.<anonymous> (_stream_readable.js:744:45)
      at IncomingMessage.EventEmitter.emit (events.js:92:17)
      at emitDataEvents (_stream_readable.js:770:10)
      at IncomingMessage.Readable.on (_stream_readable.js:691:5)
      at OverridenClientRequest.<anonymous> (/Users/pavlo/Projects/bamboo-api/node_modules/request/main.js:611:16)
      at OverridenClientRequest.EventEmitter.emit (events.js:95:17)
      at /Users/pavlo/Projects/bamboo-api/node_modules/nock/lib/request_overrider.js:220:11
      at process._tickCallback (node.js:419:13)

  6) bamboo.getAllPlans returns a string saying that there are no plans:
     TypeError: Cannot read property 'readable' of undefined
      at IncomingMessage._read (http.js:347:18)
      at IncomingMessage.Readable.read (_stream_readable.js:320:10)
      at IncomingMessage.read (http.js:339:15)
      at IncomingMessage.<anonymous> (_stream_readable.js:744:45)
      at IncomingMessage.EventEmitter.emit (events.js:92:17)
      at emitDataEvents (_stream_readable.js:770:10)
      at IncomingMessage.Readable.on (_stream_readable.js:691:5)
      at OverridenClientRequest.<anonymous> (/Users/pavlo/Projects/bamboo-api/node_modules/request/main.js:611:16)
      at OverridenClientRequest.EventEmitter.emit (events.js:95:17)
      at /Users/pavlo/Projects/bamboo-api/node_modules/nock/lib/request_overrider.js:220:11
      at process._tickCallback (node.js:419:13)


npm ERR! Test failed.  See above for more details.
npm ERR! not ok code 0
```

Found that is bug in old version of module 'nock': https://github.com/pgte/nock/issues/146

So updated version of mocha and nock, should fix issues with tests.