Setup unit tests and integration tests for Sparkler

[thammegowda]

To begin with, write unit tests for :

• test RDD functions
• Test core functionality of plugins

Tasks

• [X] Setup a web server for testing
  • [X] Bind it to junit to auto start and stop while running the tests
• [X] Setup a solr instance for testing
  • [X] Bind it to junit to auto start and stop
• [X] Test Default Fetcher
• [ ] Test Javascript Engine functionality
• [ ] Test URL filters
• [ ] Test Fetch Function
• [ ] Test Parse Function
• [ ] Test Seed Injection
• [ ] Test URL Normalizer
• [ ] Test HDFS persistance
• [ ] Test Kafka Output

PS: The current progress can be tracked on https://github.com/USCDataScience/sparkler/tree/unittests branch