Started develop branch from 0.3.0
cluda/kernel: fixed copy-paste introduced bug in function names
cluda/kernel: added handler for norm()
doc/introduction: fixed python 2.x print usage
TODO: removed old 0.2.0 task
fft: removed unused keyword
matrixmul: now accepts a vector in place of ``a`` (isn't very fast, just a placeholder for use by DHT)
dht: committed initial version
dht: explicit cast to float before calling sqrt() - otherwise numpy cannot find an ufunc to deal with long
fht: testing for the equal length of input and output shapes
dht: added missing tr_axes derivation
dht: fixed bug in the calculation of dot result shape
dht: fixed transposition axes for the final transposition
test/test_computations: added some basic tests for the first-order DHT

Currently 1D and 2D tests pass, and 3D tests fail.
test/test_computations/test_dht: filling test arrays with sparse modes to speed up testing
dht: removed debug print
test/computations/transpose: fixed variable name
TODO: added task
test/pytest_returnvalues: added missing return, which finishes callback processing thus avoiding double executions of the same testcase
operation: fixed bug with kernel argument names conversion when adding a nested computation

Added the second kernel to Dummy in test/test_core.py, so that this bug is caught in test_nested()