modularize the current codebase

[mratanusarkar]

The current implementation should be more generated and made modular by breaking codebase into the following logical blocks:

1. The scraper
2. The word counter
3. The word cloud generator

[mratanusarkar]

also, the preprocessing and data cleaning functions should be moved to a new logical block and de-coupled from generator.py.

Ideally, (with the current scope) I see potential for the following:

• scraper.py
• preprocessor.py
• generator.py -> visualizer .py