- added template for request body which takes either a string
build with form data or the json or text input given as it
- added template for setting content type in header for
multipart/form-data file format
- passing the request-body in setopt method to set the request
body
- added functions to build formdata with or without a File
- a constructor which takes a human readable name and the file
and internally stores the contents of the file
- if the file does not exist, then file_get_contents function
returns false, in that case the contents of the file is an empty
string
