update user contribute lib
Issue 3: added contrib to the distribution and added included them in the admb scripts.
Added build files for contributed libraries.To use:$ make --directory=scripts/configure$ ./configure$ make$ make contrib
overload likelihood functions for random effect, and change the format, the old one from VC++ editor looks not good in redmine.
user contribute library from weihai, some useful functions for doing simulation in admb and overloaded functions of negative log likelihood for some distributions