ROSS core hacking for 2nd stage init is complete.  This will break
all of the models.  Have a nice day.
Updated all models to put NULL into slot for new pre_run_f function.
Fixed error message inside of tw_pre_run_lps().
Added a pre_run example function for phold.  Left off by default.
Added OMNet schedulers.
Merge branch 'pre_run'