Added option arguments description on `Engine` constructor
Added `.DS_Store` to `.gitignore`
Added to `run-flow all-sequences` ability of 1st yield without sequence

I added to `run-flow all-sequences` the ability to call 1st yield without
any sequence and implemented test case for it
Test cae for `run-flow all-sequences` with sequences with no arguments

I added test case for `run-flow all-sequences` to test running sequences with
no arguments