possible bug in Mason

Switching to devel mailing list:

Here's a diff of Mason 1.35 v.s. Mason 1.36 but I've not had time to look closely... thought I was on to something with there being two http_header_sent methods (FakeApache.pm and ApacheHandler.pm), but then noticed that 1.35 and 1.36 seem to have the same code for that.