python tools visual studio - step into not working
workaround rather than full answer.
I encountered this problem while importing my own module which ran code (which was erroring) on import.
By setting the imported module to the startup script, I was able to step through the startup code in the module and  debug.
My best guess is that visual studio 2015 decided the imported module was a python standard library, but it really isn't viable to turn on the 'debug standard library option' as many standard library modules generate errors on import themselves.
I am trying to debug a scrapy project , built in Python 2.7.1 
in visual studio 2013. 
I am able to reach breakpoints, but when I do step into/ step over
the debugger seems to continue the exceution as if I did resume (F5).
I am working with standard python launcher.
Any idea how to make the step into/over functionality work?