Code Listener's settings can be now controled from user's environment.

You can set these settings below as your permament shell environment
same as you would do in cl/config_cl.h file. Please note, that the
colorized output of the ClPrettyPrint() can be now paremeterized also.
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  CL_DEBUG_COLORED_OUTPUT
  CL_DEBUG_CLF
  CL_DEBUG_GCC_GIMPLE
  CL_DEBUG_GCC_TREE
  CL_DEBUG_LOCATION
  CL_DEBUG_LOOP_SCAN
  CL_DEBUG_POINTS_TO
  CL_DEBUG_VAR_KILLER
  CL_EASY_TIMER
  CL_MSG_SQUEEZE_REPEATS
  CLPLUG_SILENT
  DEBUG_CL_FACTORY