Deprecate Fixed Point library

Type of change

The following changes have been made:

The FP lib requires a substantial re-write and is currently not fit for production. This PR removes the FP lib and it's associated elements in the repo.
A note has been left on the repo's README explaining that the FP lib as been deprecated/removed pending a re-write.

As the FP lib was not fit for production I have opted for removal as opposed to archival. An issue to re-write the FP lib has been added to the repo.

Closes #277

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