[pipes-functions] Adding exit-status, concat, args and close functions

[pratikmota]

Changes:

1. Adding new 4 functions
2. exit-status, concat, args and close function

Testing:

• when closeis successful it will return nil so nothing is display in error
• argsi tried to check, I am bit confuse how to test it. As it will be used to take command line argument of mainfunc.
• For concat i created locala.txt andb.txt for testing.