User_nicename now mapped to samaccountname

Fixed #34- User_nicename was being mapped to uid (for some users its sid).
Updated it to map to sanitized(replace all special characters with
 alphanumeric characters) samaccountname.
Merge pull request #35 from TriptiSharma/dev

User_nicename now mapped to samaccountname
Bump version to v1.2.1.0 for release