spawn: autoload_functions better detection

[icasimpan]

autoload_functions is commonly used as follows:

## list of functions to auto-load
function_to_autoload="
banner
greet
"

autoload_functions "$function_to_autoload"

and it's fine. Spawn understands it.

However, when list of functions is listed this way:

function_to_autoload="banner greet"

it breaks.

Issue is the line function: core/lib/getdeps_indirect.bash.inc

   echo $($CAT_BIN $file | $SED_BIN -n -e "/$deps_varname\=/,/\"/ p" | $GREP_BIN -v $deps_varname | $GREP_BIN -v '"')

[icasimpan]

Keeping this ticket open to refactor the initial fix. Hint: check the TODO list in initial fix.