Implement ANN mode readings for SRF08

[LeoColomb]

From https://www.robot-electronics.co.uk/htm/srf08tech.html

ANN mode (Artificial Neural Network) is designed to provide the multi echo data in a way that is easier to input to a neural network, at least I hope it is - I've not actually done it yet. ANN mode provides a 32 byte buffer (locations 4 to 35 inclusive) where each byte represents the 65536uS maximum flight time divided into 32 chunks of 2048uS each - equivalent to about 352mm of range. If an echo is received within a bytes time slot then it will be set to no-zero, otherwise it will be zero. So if an echo is received from within the first 352mm, location 4 will be non-zero. If an object is detected 3m away the location 12 will be non-zero (3000/352 = 8) (8+4=12). Arranging the data like this should be better for a neural net than the other formats. The input to your network should be 0 if the byte is zero and 1 if its non-zero. I have a SOFM (Self Organizing Feature Map) in mind for the neural net, but will hopefully be useful for any type.

Location 4	Location 5	Location 6	Location 7	Locations 8 - 35
0 - 352mm	353 - 705mm	706 - 1057mm	1058 - 1410mm	and so on

Locations 2,3 contain the range of the nearest object converted to inches, cm or uS and is the same as for Ranging Mode.