Fix bugs in paramsel_siglam* and compatibility fixes on testall.m

Bugs in paramsel_siglam and paramsel_siglamho when retraining with opt and
sigma was previously set.
Compatibility fixes on test_driver.m and testall.m to run (for gurls upgrade).
Compatibility checks in kernel_linear.m, kernel_rbf.m, kernel_chisquared for
newprop when opt is passed in.
Minor: edits and compatibility changes all around.