adding enable_user method to enable user

[wrighterase]

No description provided.

[tiyeuse]

Thanks for the pull request, but we can't modify the UAC attribute of an account with the hardcoded value of 512 (which stands for NORMAL_ACCOUNT). In case other attributes (such as DONT_EXPIRE_PASSWORD) are defined, they will be removed.
A bitmask operation needs to be performed in order to swap the ACCOUNTDISABLE attribute.
I will look at the changes, but meanwhile you can still use the change_uac function with the uac-decoder website to make it work:

# ldeep ldap change_uac -h
[...]
  user        Target user (dn format). Ex: "CN=bob,CN=Users,DC=CORP,DC=LOCAL"
  uac         UAC integer value. Ex: 512 for NORMAL_ACCOUNT