Directives

[jadjoubran]

As discussed in #245 by @flick36, some use cases require directives.

I'm researching the best way to fix this without creating a mess
I also need to check if it's possible to upgrade those directives later on

[jadjoubran]

• add index.directives and require it
• add note for documentation to explain difference between components & directives + link to angular docs
• add ng:directive command
• republish config