Add equivalent of object-property-newline for import declaration

[`object-property-newline`](http://eslint.org/docs/rules/object-property-newline)

> While formatting preferences are very personal, a number of style guides require that object properties be placed on separate lines for better readability.
> Another argument in favor of this style is that it improves the readability of diffs when a property is changed:

Examples of _incorrect_ code for this rule:

``` js
import {createMovieMatcher,matcher} from './../src/movieRecognizer';
```

Examples of _correct_ code for this rule:

``` js
import {
createMovieMatcher,
matcher
} from './../src/movieRecognizer';
```

Start with the linked object-property-newline rule and inspect the repository's import-related rule entry points. The change is complete when an import with multiple named specifiers is reported unless those specifiers are placed on separate lines, matching the incorrect and correct examples in the issue.

Written by the indexing model from the issue text.