Returns free params defined at command line.
Every value which is not an argument is considered to be a parameter and store to be returned by this function.
An example about using this function could be the next. A program have defined several arguments using the function exarg_install_arg but that program also needs to receive several file path. Once the exarg_parse have detected all argument, all parameters are stored to be returned on this function.
A program which may receive the argument --save-all but also several files:
a_program --save-all file1 file2 file3
Will need to call this function to get the list: file1 file2 and file3.
- the list of params for the program. The list return should not be freed