Introduce new structure Scrap and Reporter

The current FooGetter scheme has a lack of functional cohesion.
FooGetter has two responsibilities in a single class:
 1. Retrieve information from some data sources;
 2. Compose a message for tweeting

Now, Scrap is responsible for acquisition and storage of information,
Reporter makes a message by using information form Scrap.

This change will make one Reporter could utilize multiple data sources
to compose more complicated (funny) messages.
Remove currently unused functions
Introduce --test option for checking messages without actual tweets
Use new Scrap and Reporter