General Cross-validation: update for GPDB40, 41 and PG84

Solved some compatibility issues
Module Name: General Cross-validation

Fixed a typo
Linear Ridge regression together with cross-validation support
Linear Ridge Regression

Minor change due to the interface change of __cv_summarize_result(...)
Linear LASSO regression using IGD algorithm with cross-validation
support
Linear LASSO Regression

Minor change due to the interface change of __cv_summarize_result(...)
Elastic Net

will finish IGD, FISTA, CD, BCD optimizers

will add cross-validation support