Introduction of a Configuration Builder

Reopened from GitHub Pull Request #1

Description copied from GitHub:

What has changed:

• new class ConfigurationBuilder with static from() method
• new (non-static) method from in Configuration, which creates a builder for this specific Configuration
• let pre-defined stages extend AbstractTransformation or implement ITransformation whenever possible
• adjustment of examples (in test directory)

Future work could be:

• Support for distribution/merging
• Introduction of a composite stage builder
• .toActive(stage) and .endActive(stage) methods that connect the stage and additionally set it active

Some documentation written in markdown can be found here: TeeTime Configuration Builder Documentation

When moving this documentation to any "official" place, maybe the Future work section should be removed.