Support ":breakadd here" inside functions

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Add "breakadd here" inside function body
2. Call the function

What is the expected output? What do you see instead?
Vim should enter debugging mode when executing the given line of code instead 
of throwing "E32: No file name".

What version of the product are you using? On what operating system?
Vim 7.4.622 on Ubuntu 14.04

This is a feature request. It's documented in the help for :breakadd that it's 
not supported inside functions.

Original issue reported on code.google.com by daviebd...@gmail.com on 22 Mar 2015 at 9:09