create struct buffer_t, use in updater
update to clang-format 3.4
fix unlikely uninitialized value
rename functions/variables for clarity
invert default return value

Prior to 643886b916fdde the program exit status was updated to 0 at the
start of iteration over search results. The aforementioned commit
removed this, which caused list actions to wrongly exit 0 when they had
no matches.