Add 'content-length' header to DELETE requests that include body
Add 'content-length' header to DELETE requests that include body

* i.e. Cowboy server ignores the body otherwise
* RFC RFC2616: the presence of a message-body is signaled by the inclusion of a Content-Length or Transfer-Encoding header (section 4.3)

Conflicts:
	src/lhttpc_lib.erl

Licenser/lhttpc