Changing the NH utility for options

NH utility is changed like below. 

# nh
Usage: --list
       --get <nh_id>
       --help

    --list Lists All Nexthops
    --get  <nh_id> Displays nexthop corresponding to <nh_id>
    --help Displays this help message




Usage with exampls:
-------------------

1) nh --list lists all nexthops

nh --list 

Id:000  Type:Drop      Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:1

Id:001  Type:Resolve   Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:235

Id:002  Type:Encap     Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:1
        EncapFmly:0806 Oif:0 Len:14 Data:00 00 00 00 00 01 00 25 90 c3 08 82 08 00

Id:003  Type:Receieve  Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:4
        Oif:1

Id:004  Type:Receieve  Fmly: AF_INET  Flags:Valid, Policy,   Rid:0  Ref_cnt:1
        Oif:1

Id:005  Type:Encap     Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:767
        EncapFmly:0806 Oif:2 Len:14 Data:2c 21 72 a0 4a 80 00 25 90 c3 08 82 08 00

Id:006  Type:Encap     Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:2
        EncapFmly:0806 Oif:2 Len:14 Data:00 25 90 c3 0a f6 00 25 90 c3 08 82 08 00

Id:007  Type:Encap     Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:2
        EncapFmly:0806 Oif:2 Len:14 Data:00 25 90 c4 81 ae 00 25 90 c3 08 82 08 00

Id:008  Type:Encap     Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:2
        EncapFmly:0806 Oif:2 Len:14 Data:00 25 90 c4 7a 70 00 25 90 c3 08 82 08 00

Id:009  Type:Encap     Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:2
        EncapFmly:0806 Oif:2 Len:14 Data:00 25 90 c4 7a 9e 00 25 90 c3 08 82 08 00

Id:010  Type:Encap     Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:2
        EncapFmly:0806 Oif:2 Len:14 Data:00 25 90 c3 3f 3c 00 25 90 c3 08 82 08 00

Id:011  Type:Encap     Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:2
        EncapFmly:0806 Oif:2 Len:14 Data:00 25 90 c5 59 b0 00 25 90 c3 08 82 08 00

Id:012  Type:Encap     Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:2
        EncapFmly:0806 Oif:2 Len:14 Data:00 25 90 c4 84 be 00 25 90 c3 08 82 08 00

2) nh --get <nh_id> Displays a particular nexthop
   
nh --get 15

Id:015  Type:Encap     Fmly: AF_INET  Flags:Valid,   Rid:0  Ref_cnt:2
        EncapFmly:0806 Oif:2 Len:14 Data:00 25 90 c3 ae b4 00 25 90 c3 08 82 08 00


nh --get 3000
Error No such file or directory in kernel operation

3) nh --help Lists the all above options
 
nh --help
Usage: --list
       --get <nh_id>
       --help

    --list Lists All Nexthops
    --get  <nh_id> Displays nexthop corresponding to <nh_id>
    --help Displays this help message