escape ()\* chars in LDAP DN string (as per ldap-filter 0.3.0 breaking change)

[delfuego]

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[delfuego]

@gheeres Just an FYI that this resolves a breaking change in ldap-filter (that node-activedirectory depends on as a child dependency). I noticed the breaking change in ldap-filter 0.3.0 when I did a full node module reinstall today on a project of mine; ldap-filter got updated from 0.2.3 to 0.3.3 and many of my users could no longer log into the project. It turned out to be only the users who belonged to an AD group that has a parentheses character in its name.

This pull request properly-escapes the four characters that were added as mandatory-escape characters in ldap-filter 0.3.0.

I tested this change for all versions of ldap-filter between 0.2.2 and 0.3.3 (current), so it should not break projects that still have package-lock'ed versions of ldap-filter prior to (or later than) 0.3.0.