Output ep_log_mix errors to stderr
Add one more TODO item
Add dependency on Thud
Use thud_is_bool instead of ep_bool_is_valid
Remove unused ep_attrs_set_shellopts
Use thud_attrs_* instead of ep_attrs_*
Use thud_str_* instead of ep_strstack_*
Use thud_arr_* instead of ep_arrstack_*
Use thud_backtrace instead of ep_backtrace
Use thud_abort instead of ep_abort
Fix missing getopt handling
Make ep_abort_if_not accept eval arguments
Use thud_assert instead of ep_abort_if_not
Move getopt check to _ep_shell_init

Move enhanced getopt presence check from ep_util.sh to _ep_shell_init.
Remove ep_util.sh as it is now empty.
Use thud_get_pid to get current shell PID

Use thud_get_pid to get current shell PID, update the comment to mention
updated thud_abort_frame behavior.
Use Thud strict mode

Use Thud strict mode, which adds noclobber attribute and shiftverbose
and failglob options to previously used.