Able to get child sections

for example:
~~~
[node]
...
[node.biz1]
...
[node.biz2]
...
[node.biz3]
...
[node.bizN]
...
~~~
in this situation, we are not sure that how many child sections will appear, child section names dont even have a pattern.
so if we can do getSectionWildcard("node.*") or something like that, it will be very handy for this situation.

thanks for your great work!