RemoveHeader
status_t RemoveHeader(const char *key);
T(RemoveHeader(buffer, bytes));
RemoveHeader(net_buffer* buffer, size_t size)
RemoveHeader(fHeaders.IndexOf(header));
virtual Header* RemoveHeader(int32 index);
virtual void RemoveHeader(Header* header);
RemoveHeader(name);
fBody->RemoveHeader("Subject");
fBody->RemoveHeader("To");
fBody->RemoveHeader("From");
fBody->RemoveHeader("Reply-To");
fBody->RemoveHeader("Cc");
fBody->RemoveHeader("Priority");
fBody->RemoveHeader("X-Priority");
fBody->RemoveHeader("X-Msmail-Priority");
fBody->RemoveHeader("Date");