Deleted multiplications by zero and consequent additions of zero terms.

LevMarq now doesn't outright fail, but doesn't seem to improve things
much if at all.

Refactoring of Cholesky decomposition.
Fix for memory corruption bug.
LevMarq as a whole still non-functional.

Signed-off-by: Yan Wang <yan.wang@linux.intel.com>

This silences the pedantic warning messages from gcc 4.8.3

(performance) Possible inefficient checking for 'lmap' emptiness
(warning) Assignment of function parameter has no effect outside the function. Did you forget dereferencing it?
(style) Array index '<xxx>' is used before limits check