Alpha models can choose to implement the Name property, if not, the system
will use the model's type name as the Insight.SourceModel.
Existing tests were updated to also assert expected model names
Implements `Insight.Price` method to make it easier to create new instances of `Insight` of `InsightType.Price`.
Standardize the parameter order to `Symbol`, `TimeSpan`, `InsightType`, `InsightDirection`, `Double`, `Double`.
The term 'alpha' is used to describe the entire algorithm. Therefore, 'alpha'
produces insights. From this we have things like IAlphaModel, which is the model
defining how insights are produced. We have IAlphaHandler, which defines how the
insights from a single 'alpha' (the algorithm) are managed, analyzed, and stored.
Types closer to the individual prediction level, such as InsightDirection, or
InsightScore relate directly to exactly 1 insight. The distinction between the
two became more clear as we developed the insights API, and from that effort it
was decided to harmonize alpha/insight terminology across the various QC systems.
Michael Handschuh