Improve default scopes

[aminya]

We should add more built-in providers or offer packages that implement such providers.

Related issues:
#179
#207
#208
#182
#200
#224
#220
#260

[albert200000]

Shouldn't languages that have proper autocomplete packages be removed to avoid confusion with duplicate results? Like python, c/c++, php, ruby, javascript except coffee.

[aminya]

autocomplete-path doesn't overlap with what the languages already provide.

[albert200000]

I'm getting duplicates with atom-typescript package. I thought it's the same with other packages but probably not.

[aminya]

Please open a separate issue with a reproduction. I use atom-typescript every day, and I haven't faced this issue. So, I need more information.