Modify linear.cpp so that users can easily give initial solutions.
Modify linear.cpp so that users can easily give initial solutions.

angleto/liblinear,rokm/liblinear,Maluuba/liblinear,ShawnHuang/liblinear,toothacher17/liblinear,angleto/liblinear,ShawnHuang/liblinear,cjlin1/liblinear,cjlin1/liblinear,Maluuba/liblinear,cjlin1/liblinear,robin-lai/liblinear,robin-lai/liblinear,rokm/liblinear,angleto/liblinear,toothacher17/liblinear,Maluuba/liblinear,angleto/liblinear,Maluuba/liblinear,ShawnHuang/liblinear,toothacher17/liblinear,robin-lai/liblinear,robin-lai/liblinear,ShawnHuang/liblinear,rokm/liblinear,cjlin1/liblinear,toothacher17/liblinear,rokm/liblinear