Added control contribution to estimated controls.

I fixed the negative sign issue I had with respect to the formulation of Ax=b
and defining the test setup in TestSimpleControlSolver with a negative sign.
The estimated controls now gives the correct result and in addition some
estimates of the control contributions from the sensor error.
Fixed erroneous tests in walking data.
Improvements to the comparison plot.
Made the measured lines black.
Improvements to control contribution plots.
Removed figure size of grf plots.
x label only on last axis
Fixes incorrect deconstruction of the covariance matrices.

Takes care of issue # 8 also. I removed the check for an empty r2 norm from
lstsq and added a warning if there is rank deficiency.
Changed ommitted gains to 0.0 instead of nan.