Refactering the FISTA & IGD Python code
Refactoring FISTA & IGD C++ code
Improvement on the preformance of FISTA

* Use an adaptively changing stepsize, which is allowed to increase with
  a probability. This minimizes the performance dependence on
  max_stepsize.

* Use a smaller eta, to explore the stepsize more closely

These two decrease the running time for cvtest1 data set from 140s to
40s.
C++ coding is done
Coding for elastic net logistic models almost completed
Fixing bugs.

Logistic results are wrong. There are more bugs.
Bug fixed, and coding completed
Restore the deterministic nature of FISTA