Moved existing code into folders

Test image generation has been moved into test.
Source detection related code has been moved into source_detection

test.ipynb has been updated to reflect the code changes.

Source detection currently does NOT work
Created detection file

Refactored the source detection driver code to be less reliant
on the config file and have much more extensibility.
Merge pull request #16 from rzlee/refactor

Moving existing code into folders