Adding vcs subversion support for target-branches, target-tags with multiple endpoints.

We currently have a situation where a repository exists in the following structure:

```
src/
branches/
development/
releases/
tags/
development/
releases/
trunk/
```

From my understanding the `target-branches` can only support a string to either `branches/development`or `branches/releases`, would it be feasible to add an array check on the target-branches configurations. For example:

```
{
...
"target-branches": ["branches/releases","branches/development"],
...
}
```

Or is it possible to get all repository (containing a composer.json) end points recursively from just providing `"taget-branches":"branches"` ?