[ENHANCEMENTS]
Added clarity around preserving output order for several models;
MCE::Flow, MCE::Loop, and MCE::Step.Inlined comments in the code for overriding MCE options when using
an anonymous hash for the first argument; MCE::Flow, MCE::Step, and
MCE::Stream.Removed unnecessary code due to one not able to pass MCE options other
than through the init method for MCE::Loop, MCE::Grep, and MCE::Map.Added to doc a use-case example searching a large file with mce_grep_f.
The emphasis is comparing the memory consumption against the native
grep function as well as time to complete.