preparation of plans for SIFT
Merge remote-tracking branch 'pierre/master'
minor corrections
make preprocessing kernel 2D kernels
moved to 2D preprocessing (with tests OK)
tests
integration of convolution
tests for convolution kernels
use global worksize calculation
a couple of untested kernels
automatic calculation of workgroup size
Linear combination of two matrices
Test suite for algebra.cl -- Linear combination OK
Linear combination OK