remove support for records from auto_encode
convert most of libcore records into structs
core: convert io::Res over to the Drop trait
Remove "unsafe" from run::start_program
convert most of libstd over to structs
time tests are racing on tzset, so merge the tests together.

This attempts to fix issue #3327.
Fix a typo
Convert extfmt::rt::Conv into a struct
Convert core::pipes::{Packet,Chan_,Port_} into structs
Convert pipes::Buffer into a struct
Fix another typo
convert io wrapper records into structs
Convert dlist records into structs
Merge pull request #4613 from erickt/incoming

convert most of libcore and libstd to structs, work around tzset race