Documentation tracking issue

[henrygerardmoore]

Fuse should aim to include documentation of every concept and specific motion model in the library. Currently, much of this is missing.
It is also ideal to have examples for each major feature or concept, but documentation is a good starting point.

General concepts

• Transactions
• Optimizers
• Motion Models
• Sensor Models
• Graphs
• Constraints

Optimizers

• All

Graphs

• hash_graph

Motion Models

• Transform sensor
• All others

Sensor Models

• All

Constraints

• All