Switched from nested Lists to a single add delegate.
Added code to clean up EffectParser results.

- No tests yet. Probably lots of bugs, too.
Renamed Fluent to Effects and added EffectParserHelper tests.

- Renamed the Fluent namespace and folder to Effects.
- Added TestEffectParserHelper.cs and its tests.
- Moved EffectSpan and EffectSpanType to their own files.
- Added Equals, IEquatable<EffectSpan>, ToString and GetHashCode for
  EffectSpan.
Added UsePowerEffect.
Parses UsePowerEffect correctly.

- Need to genericize parsing so new EffectComponents can be added outside
  this assembly and without access to EffectParser internals.