add first implementation of two-channel ica

makes no assumptions on source positions, just outputs two separated
channels
make output of nsIca2 much more stable
add function to convert twin mic ica matrix to angles
remove debug messages
fix bugs, remove debug outputs
fix bugs in NS-ICA2
fix bugs in angle calculation

take absolute to prevent complex numbers
add feature to NS-ICA2

allow to switch between two modes: first mode forces each ica-outputs to
be in front or back half exclusively. second mode allows all angles for
both channels (default).

fix bug handling non-negative weights in demixing matrix when
calculating the corresponding angle
remove sorting from twinIcaToAngle

this made linking of the angle to the demixing vector impossible
remove code that had no effect

subsequent lines do the same more efficiently, therefore it was done
twice
add output variable to twinIcaToAngle

returns the corresponding betas in addition to the angle
add function to calculate first order dma pattern

returns amplification based on the amplification of the back cardioid
and the angle of incident
add function to calculate the twin mic pattern

Takes the amplification of the backwards cardioid (beta) to estimate the
pattern and an angle. Returns the amplification at this direction.
change standard behaviour of twinIcaToAngle

Standard is now _not_ to force angles in any direction.
fix bug in beta calculation in twinIcaToAngle

Backwards looking cardioids where not recognized and produced a wrong
beta.
Added tests for beta calculation.
fix bugs and add tests in twinIcaToAmp

Backwards looking cardioids where not calculated correctly.
There was a wrong vector mulitplication, which is now elementwise.
Added tests.
fix comments
add output of front amplification to twinIcaToAmp
add function for twin mic algorithms

calculates a mixing matrix out of a pair of null angles
add function for twin mic processing

returns the weight of the back cardioid for a given null angle