* add ability to find recipes in subfolders: message if ambiguities

as user I see it like this:

    write a recipe and put it somewhere in below the defined location: /anaconda_dir/conda-recipes
    Than just build the package per name.

    if there are ambiguities: specify the full path

output in such an case:

```
workerm@notebookpc:~/anaconda/bin$ ./conda-build appdirs

Multiple recipes with same name: <appdirs>
     /home/workerm/anaconda/conda-recipes/appdirs
     /home/workerm/anaconda/conda-recipes/Untitled Folder/appdirs
Ambiguities: specify full recipe path
workerm@notebookpc:~/anaconda/bin$ 
```