Made a simple fetcher that fetches page content.

Made a simple fetcher class that fetches page content from the internet.
Simply downloads the content; it doesn't have any kind of timeout or
anything.
Made a Miner class which contains components.

Created a Miner class which contains components, each of which process
data.
A simple link extractor component was also created. This Component will
be coupled with a LinkSanitiser component, to ake the links safe to
store/use for the agent.