Add Sphinx docs config.

Added documentation links to Scratch Radio Wiki.

Replaced reference to gr-osmosdr with gr-limesdr in readme file.

Remove unused interpolation and decimation CIC filters.

Removed unused sample rate conversion blocks.

Updated images to remove Lua Radio references

Changed extension name, which meant examples had to be reimplemented

Initialise OOK modulator rate limiting on first call.

Fixed receive message handling in the Scratch extension file.

Revert "Fixed message buffer allocations."

Fixed message buffer allocations.

Updated examples to include radio source and sink gains

Added gain setting to radio source and sink blocks.

Reduced modem bit rate and updated examples

Updated examples for single node.