add model uncertainty estimation with random models, also indent all the
code to make them a little bit easy to read
bug fix about shift when output the velocity model
segmentation fault appears in the case of very large dataset, there will be problem if the nonzeros of G matrix exceed the range of INTEGER, now change maxnar = spfra*dall*nx*ny*nz, remember order matters.
also show the lat and lon when station outside the inverted region
