Trigger _set_status('error') on _set_error()
Handle M3UE directives using callbacks
t: Output note about what URI is being tested
t: make ref val for status attribute overrideable
t: test uri attribute
t: refactor out tests for valid HLS objects
Initial support for variants in playlist
t: tests for variants
Update README about segfault bugs in Perl

The use of Regexp::Grammars causes Perl to segfault/have some kind
of memory corruption when trying to load large M3UE files.

See also: https://rt.cpan.org/Ticket/Display.html?id=60109