Support for fixed number of iterations on the CPU
Optimizations to CPU LMA code

Matrix is symmetric, so only half the computations for the alpha matrix
need to be computed, the other half can be mirrored.
Removed the weights from the computation (we don’t use them, yet)
Removed a redundant matrix inversion call from the computation of the
standard error estimation.
Improved performance CPU fitting

Much (much!) faster fitting on the CPU
Merge pull request #2 from ekatrukha/cpu-fixed-iterations

Cpu fixed iterations