use debug_safe in postfork do_builtin_io. Closes #495
Fix for issue where completing in the middle of a command may append extra junk at the end of the completions in the list
https://github.com/fish-shell/fish-shell/issues/301
Don't call expand_home_directory from within parser_t::test - it may hang
https://github.com/fish-shell/fish-shell/issues/512
Formatting
Added a seq function that defers to the seq command if present
https://github.com/fish-shell/fish-shell/issues/137
Remove seq.in, in favor of the new function. Remove seq detection from configure.ac. Teach the Makefile how to remove old installed seqs.
Actually add the seq function (oops)
Make umask work on OS X
https://github.com/fish-shell/fish-shell/issues/515
stop profile switch from crashing (issue #517); also make print_profile use a loop instead of recursion
fix a memory leak in profiling, add a profiling test
Fix for missing first character in completions
Fix proc and pid completion on OS X, and improve it on Linux.
https://github.com/fish-shell/fish-shell/pull/129
Ajax fix for Firefox, it isn't XML.
Formatting
rename enum io_mode -> io_mode_t; make io_data_t::io_mode that type
Use new IO_INVALID as default value of io_data_t::io_mode
Make io_data_t destructor virtual
Introduce a macro CAST_INIT to abbreviate common static_cast's a bit

This macro doesn't work with type names containing commas, but that doesn't
seem to be too common in fish.
Let io_data_t constructor take optional io_mode and fd
Put io_data_t detail printing in virtual io_data_t::print