Add extra hints in README.md for new developers
Add extra hints in README.md for new developers

Not knowing gulp and electron beforehand, could make it a bit difficult
to start out. It took me quite some fiddling and looking at misleading
error messages to figure out I should have installed `gulp` before
running `npm install` (whereas I assumed npm would install it for me).

The electron binary, also, isn't directly available as a command since
npm does not put it on the $PATH for you. So I added a hint to where the
binary is located.

refack/yakyak,bseber/yakyak,bseber/yakyak,averissimo/yakyak,yakyak/yakyak,yakyak/yakyak,refack/yakyak,refack/yakyak,arnriu/yakyak,arnriu/yakyak,monchote/yakyak,yakyak/yakyak,averissimo/yakyak,arnriu/yakyak,averissimo/yakyak,monchote/yakyak,bseber/yakyak,monchote/yakyak