SUGGESTION: string version of sequence of attributes

The following piece of code could be added in the source code, which allows using `myboxobj("a.b.c.d")` instead of `myboxobj.a.b.c.d`. This simplifies some dynamic coding.

~~~python
#!/usr/bin/env python3

from box import Box

# ---------------------- #
# -- BETTER BOX CLASS -- #
# ---------------------- #

###
# We make the class Box callable to allow the use of virtual
# pointed paths.
###
class BoxPlus(Box):
###
# prototype::
# content : a pointed path similar to a sequence of
# attribute request.
#
# :return: the expected value.
###
def __call__(
self,
str_attrs
):
val = self

for n in str_attrs.split('.'):
val = getattr(val, n)

return val
~~~