CDAP-730 Added capability to start a program with runtime args and to set/get runtime args

* StartProgramCommand now supports runtime args
* Added SetProgramRuntimeArgs and GetProgramRuntimeArgs
* Refactored CLIMainTest to multiple test methods
Shouldn't you test and see if runtimeArgsString == "" and in that case use
"Successfully started %s '%s' of application '%s'\n"
as it does currently?