Allow providing no depth and falling back.
Provide more state information in reprs.
provide more logging.
pattern for patternatlas.
Can be enabled like so:
```
from patternatlas import is_pattern
from menuhin.patterns import menuhin_breadcrumbs
@is_pattern(assets={'top': ['css/myfilename.css']})
def breadcrumbs(request):
    return menuhin_breadcrumbs(request)
```
turn the extra context into a caching property, assuming that the context wont change over the lifetime of the instance.
poor man's implementation of from and to depths.