Improve ldapsearch function
Improve ldapsearch function

- Check result of Connection.search() before iterating through records
- Allow attributes passed to Connection.search() to be overridden
- Expand docstring

PSU-OIT-ARC/django-arcutils,wylee/django-arcutils,PSU-OIT-ARC/django-arcutils,kfarr2/django-arcutils,mdj2/django-arcutils,wylee/django-arcutils,mdj2/django-arcutils