automate main.py run through tweets written

* **I'm submitting a ...**
- [ ] bug report
- [ ] feature request
- [x] change/modification
- [ ] design issue

* **What is the current behavior?**

* **What is the expected behavior?**

We are currently having two independent steps in running the application

- run the stream.py to start generating tweets / statuses in tweets.json file fetched from the twitter API
- once a significant number of tweets are accumulated, run the main.py file

We need to move towards a single entry point, ensuring that the main module is started automatically.

How it can be tackled :
- count the number of tweets written explicitly and trigger a main file run once a certain no. is reached.
- keep monitoring the tweets.json file written for no. of lines written (since each status/tweet is written in new line ) using a continuous loop until the desired number is reached then exit and let it continue with execution of the main file

Or if there are better alternatives then please suggest