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
Merge branch 'develop' into feature/DHT

Need bugfix for nested computations, otherwise DHT does not work
dht: optimized transpositions in multi-dimensional cases

Now nested executions of Transpose contain only one kernel each
matrixmul: added dependencies between arguments
operation: not ignoring dependencies between external arguments
operation: forgot to add dependencies in the reverse direction (the dependency graph must be bidirectional)
Merge branch 'develop' into feature/DHT
test/computations/dht: reworked TestFunction to support missing batches, complex coefficients and custom mode data
test/computations/dht: added 1D, 50 modes case to test list
test/computations/dht: added ability to use non-random mode coefficients
test/computations/dht: setting non-zero corner modes in all tests