tests: Now can specify tests on commandline
tests: Now can specify tests on commandline

Rather than the old --script commandline option, you
can now launch tests using the tests module itself:
 ./pox.py tests --topology.topology topology

This is a first pass at this, and will probably
evolve as we flesh out unit testing.

kulawczukmarcin/mypox,diogommartins/pox,kulawczukmarcin/mypox,waltznetworks/pox,VamsikrishnaNallabothu/pox,waltznetworks/pox,denovogroup/pox,VamsikrishnaNallabothu/pox,jacobq/csci5221-viro-project,andiwundsam/_of_normalize,andiwundsam/_of_normalize,carlye566/IoT-POX,pthien92/sdn,pthien92/sdn,adusia/pox,kavitshah8/SDNDeveloper,andiwundsam/_of_normalize,chenyuntc/pox,adusia/pox,kulawczukmarcin/mypox,noxrepo/pox,pthien92/sdn,xAKLx/pox,kavitshah8/SDNDeveloper,MurphyMc/pox,denovogroup/pox,chenyuntc/pox,waltznetworks/pox,kpengboy/pox-exercise,waltznetworks/pox,diogommartins/pox,PrincetonUniversity/pox,kavitshah8/SDNDeveloper,MurphyMc/pox,pthien92/sdn,diogommartins/pox,pthien92/sdn,diogommartins/pox,diogommartins/pox,xAKLx/pox,VamsikrishnaNallabothu/pox,adusia/pox,PrincetonUniversity/pox,MurphyMc/pox,MurphyMc/pox,xAKLx/pox,VamsikrishnaNallabothu/pox,kpengboy/pox-exercise,noxrepo/pox,carlye566/IoT-POX,kavitshah8/SDNDeveloper,MurphyMc/pox,denovogroup/pox,carlye566/IoT-POX,denovogroup/pox,jacobq/csci5221-viro-project,PrincetonUniversity/pox,jacobq/csci5221-viro-project,kpengboy/pox-exercise,adusia/pox,waltznetworks/pox,kulawczukmarcin/mypox,noxrepo/pox,noxrepo/pox,xAKLx/pox,carlye566/IoT-POX,kpengboy/pox-exercise,chenyuntc/pox,carlye566/IoT-POX,VamsikrishnaNallabothu/pox,kulawczukmarcin/mypox,PrincetonUniversity/pox,jacobq/csci5221-viro-project,denovogroup/pox,kpengboy/pox-exercise,xAKLx/pox,chenyuntc/pox,jacobq/csci5221-viro-project,chenyuntc/pox,PrincetonUniversity/pox,adusia/pox,andiwundsam/_of_normalize