Added header placeholder and loader spinner (in case page takes long time to load)
Added header placeholder and loader spinner (in case page takes long time to load)

postmanlabs/httpbin,krissman/httpbin,krissman/httpbin,Runscope/httpbin,ewdurbin/httpbin,Runscope/httpbin,postmanlabs/httpbin,ewdurbin/httpbin,kennethreitz/httpbin,kennethreitz/httpbin