Added http header related features. It means we can change http header by setting a list ourself.

Wrapped more cURL constants.

Added `release_item' in {CURL_FORM} which is useful to clean the {CURL_FORM} generated by {CURL_EXTERNALS}.formadd_string_string.

git-svn-id: https://svn.origo.ethz.ch/eiffelstudio/trunk/Src/library/cURL@71685 8089f293-4706-0410-a29e-feb5c42a2edf

curl_form.e

@@ -62,6 +62,13 @@ feature -- Command
 			end
 		end
 
+	release_item is
+			-- Release item
+			-- NOT free memory! This is useful if Current generated by {CURL_EXTERNALS}.formadd_string_string.
+		do
+			item := default_pointer
+		end
+
 feature {CURL_EXTERNALS} -- Internal command	
 
 	set_item (a_item: POINTER) is