a number of speed optimizations
another small TLC5940 optimization: got rid of multiplication in indexing of column data
Split the dataloading into pre-loading and flipping the switch on.
Testing the full 120 pixel load. All speed optimizations turned on
Optimized up to 1.8944ms /column load for the TLC version
Also the genimg now can output columns as the second dimension (and does so by default)
Set compile optimization level to 2
Added more comments about conditional compilation.  About to remove some unused code
Removed some non-optimized code from TLC5940 load
Unrolling the unit loop helps, but not enough.
Almost completely unrolled version of TLC5940 load
Cleaning up the timing calculations
Revert "Almost completely unrolled version of TLC5940 load"

This reverts commit df092ecc6e176989cb39031d3abdd6f8b06828e9.
Some code cleanup
Initial version of output speed writeup