adds '-append' to stom.saveResults and fixes a bug in makeSerpInp

Modifies stom.saveResults to save all simulation results in one
file named "allresults.mat".
Fixes a bug in stom.makeSerpInp. if input variable is str it will
use all of it, if other it will take only first element.
modifies readme.md and adds manual.md to doc/ folder.