Class browse_node 's parent_path is case sensitive

Some time after I used a group type repository and added many different proxy or hosted repository as members for the group.

I found it would get different results when browse the components in html view by direct input same component's url which only the case of the name is different.

for example:

In Pypi.org

https://pypi.org/simple/cython/

and

https://pypi.org/simple/Cython/

both will redirect to 

https://pypi.org/simple/cython/

but Nexus

http://127.0.0.1:8081/service/rest/repository/browse/pypi-public/cython/

and 
http://127.0.0.1:8081/ service/rest/repository/browse/pypi-public/Cython/

will get different results on html view

After I tried to debug and find the reason by myself, I found that the parent_path property of class browse_node default collcate is "cs" not "ci"

In my opinion, Maybe case insensitive is a more suitable collate for browse_node class's parent_path property