adds lscgroup tool

adds lscgroup tool

Description:
	create tool which shows cgroups which are on system:

Usage: lscgroup [<controllers>:<path>] [...]
	list all cgroups

Changes since V1(the previous versions was not enumerated):
	* fix the format of comments which have more than 1 line
	* printf of help -> fprintf(stdout,...
	* change the sequence of processing of cgroups on input (now
    first) and internal controller list(first in the previous version), now the
    cgroups are output in order in which they are put to input
	* fix return values/error messages - now if the controller is not mount
    the tool return error - it returns 0 otherwise
Changes since V2
    * fix problem with slash characters
  (	$ lscgroup cpu:/1/2
 		cpu:/1/2/
 		cpu:/1/2/1
 	$ lscgroup cpu:1/2
 		cpu:/2/
 		cpu:/2/1 )
Changes since V3
    * rename the variables (dp1 -> cgroup_dir_path, dp2 -> input_dir_path)
    * improve the coding style

Examples:
    $ lscgroup
    devices:/
    devices:/sysdefault
    cpuset,cpuacct:/
    cpuset,cpuacct:/sysdefault
    cpuset,cpuacct:/daemons
    cpuset,cpuacct:/daemons/ftp

    $ lscgroup cpuset:/
    cpuset,cpuacct:/
    cpuset,cpuacct:/sysdefault
    cpuset,cpuacct:/daemons
    cpuset,cpuacct:/daemons/ftp

    $ lscgroup cpuset:/daemons
    cpuset,cpuacct:/daemons/
    cpuset,cpuacct:/daemons/ftp

Signed-off-by: Ivana Hutarova Varekova <varekova@redhat.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>