Improve UX adding short syntax passing string reference to methods' calls

[xepozz]

I think passing string reference could be more convenient for users:
Determine the behaviour of passing strings:

1. Hidden/short reference

'addAdapters()' => 'tag@adapters'

2. Direct/full reference

'addAdapters()' => [Reference::to('tag@adapters')]

There are short and full form. They are fully equals by meaning.

If you need to pass 'tag@adapters' as a string parameter you need to use the following syntax:

'addAdapters()' => ['tag@adapters']

That how it works now.