Add functionality to searchspider.py to search multiple keywords

[tunglinn]

Overview

Currently, searchspider only searches for 1 keyword. The goal is to be able to keep searching for the next keyword until some condition is met.
An easy first condition is keep searching until results appear, and then scrape the first URL.

Action Items

• Add functionality
• Update/add documentation, including docstring, readme, wiki

Resources

• keyword[0] is being used as the only keyword in searchspider.py
• scrapy spiders docs