fix(core): Update npm commands and documentation

[simison]

Removes deprecated onlyChanged npm script. Watch now always runs only changed tests, no parameter needed.

Change to gulp tasks was in this commit: eaead7a

[simison]

BTW I'm always a bit unsure how should I scope these fixes... "core", "npm", "build"?

[simison]

Actually the whole thing should be called test:server:watch...

[lirantal]

@simisonbuild is a good way to scope them.

[simison]

Consider this still WIP, I'll add docs for this, too.

[mleanos]

LGTM.

[simison]

Aight updated the documentation. How does it look to you now?

I basically wiped out mentions of Grunt and left Gulp there but everything directs towards npm commands. Preview README.md

I would've removed all the grunt modules and stuff, but I noticed it's still used for coverage tests... so perhaps that's a task for another PR. Edit: Seems like it's taken care of by @hyperreality : #1175 (comment)

[simison]

(squashed + reflected updates at commit message)

[lirantal]

Looks good, thanks.
P.S. you don't need to rebase and squash your commits, we can do it for you when we merge it in, just in case it's a bother for you.

[simison]

👍

you don't need to rebase and squash your commits, we can do it for you when we merge it in, just in case it's a bother for you.

Yeah, I know. Just I wanted to rewrite the commit message.