added custom header example
added custom header example

cwoloszynski/SwiftHTTP,raheelahmad/SwiftHTTP,msdgwzhy6/SwiftHTTP,sunfei/SwiftHTTP,upf/SwiftHTTP,daltoniam/SwiftHTTP,raheelahmad/SwiftHTTP,cwoloszynski/SwiftHTTP,modulexcite/SwiftHTTP,yyMlv/SwiftHTTP,ceosilvajr/SwiftHTTP,iThanh/SwiftHTTP,ceosilvajr/SwiftHTTP,upf/SwiftHTTP,msdgwzhy6/SwiftHTTP,jhinsel/SwiftHTTP,modulexcite/SwiftHTTP,alex-learn/SwiftHTTP,ohad7/SwiftHTTP,msdgwzhy6/SwiftHTTP,ChinaPicture/SwiftHTTP,tanimislam/SwiftHTTP,sunfei/SwiftHTTP,yyMlv/SwiftHTTP,tanimislam/SwiftHTTP,xiexinze/SwiftHTTP,jhinsel/SwiftHTTP,ceosilvajr/SwiftHTTP,sunfei/SwiftHTTP,ohad7/SwiftHTTP,modulexcite/SwiftHTTP,iThanh/SwiftHTTP,xiexinze/SwiftHTTP,yyMlv/SwiftHTTP,krin-san/SwiftHTTP,mtdtao/SwiftHTTP,mtdtao/SwiftHTTP,ohad7/SwiftHTTP,krin-san/SwiftHTTP,ChinaPicture/SwiftHTTP,tanimislam/SwiftHTTP,mtdtao/SwiftHTTP,alex-learn/SwiftHTTP,daltoniam/SwiftHTTP,ChinaPicture/SwiftHTTP,krin-san/SwiftHTTP,raheelahmad/SwiftHTTP