When creating, nodes and weight values are now set to zero. A couple of
other minor changes
Changed type of R, G, B variables to Uint8 from int (image.c)
When resetting matrix targets, the check for not doing it twice was
wrong when a node receives input to multiple targets. Needs to be redone
keeping track of pointers rather than variable indices
Same as previous commit
Added habituation op for node variables
Amended documentation to gpiosensor
Updated delta rule wop to work with sparse matrices
Updated TODO list