default content-type headerfield added. -'application/x-www-form-urlencoded'

if you don't insert this field in condition of POST, it's ok.
but in condition of PUT , if you don't insert this field, it doesn't work properly.
added attachment file Content-type in 'multipart/form-data'
change indentation style.
Merge pull request #37 from uzysjung/master

About Content type.