Removed bogus checkin for target.mk
Simplified simd_vector operations
Added activation enum printing; improved profile timing
Added batch size, various training precision improvements
Added letters dataset
Optimized for small batch sizes by not accumulating too many updates
Removed verbose output
Split off activation functions from perceptron to allow including into CUDA code
Added CUDA dependency to the boosting library; will need compile-time detection to do this reliably in the future
Added the CUDA backprop.  Far from finished but taking shape.
Finished (but not tested) CUDA backprop function and started driver code
Removed flayers
CUDA backprop now compiles and is implemented
Enabled device emulation to start testing code; various CUDA bugs worked around including optimization; various small bugfixes in CUDA backprop
More trying to get CUDA backprop to go...
Fixed all valgrind errors in device emulation; updates are still zero
Fixed dependency generation for CUDA
CUDA backprop now running (slowly!) but giving incorrect results
Don't require atomic updates on the threads in the update code
Fixed problem where we forgot to use the bias