Add res_config_ldap for realtime LDAP engine.

(closes issue #5768)
 Reported by: mguesdon
 Patches: 
       res_config_ldap-v0.7.tar.gz uploaded by mguesdon (license 121)
       res_ldap.conf.sample uploaded by suretec (license 70)
       asterisk-v3.1.4.ldif uploaded by suretec (license 70)
       asterisk-v3.1.4.schema uploaded by suretec (license 70)
 Tested by: oej, mguesdon, suretec, cthorner


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@99696 65c4cc65-6c06-0410-ace0-fbb531ad65f3

doc/ldap.txt

@@ -0,0 +1,65 @@
+Asterisk Realtime LDAP Driver
+---------------------------
+
+With this driver Asterisk can retrieve information from a LDAP drectory, including 
+sip/iax users, extensions and configuration.
+
+See configs/res_ldap.conf.sample for a configuration file sample
+
+
+Here is a LDAP dif sample:
+
+# Base SIP Phones Entry
+dn: uid=phone-base,dc=myDomain,dc=myDomainExt
+objectClass: top
+objectClass: AstAccount
+objectClass: AstAccountSIP
+uid: phone-base
+AstAccountAccountingCode: baseacccode
+AstAccountHost: dynamic
+preferredLanguage: FR
+AstAccountAMAFlags: billing
+AstAccountContext: ldaptest
+
+
+# A Phone. realmedPassword md5 hash should be the result of 
+#  echo -n "UID:SIPRealm:Password" | md5sum
+dn: uid=phone-test,dc=myDomain,dc=myDomainExt
+objectClass: top
+objectClass: AstAccount
+objectClass: AstAccountSIP
+uid: phone-test
+AstAccountAccountingCode: acc-phone-base
+AstAccountFullContact: Noone <1234>
+AstAccountCallerID: 1234
+AstAccountBaseDN: uid=phone-base,dc=myDomain,dc=myDomainExt
+realmedPassword: {MD5}f67965da780bf9c70d6e337f938cee6f
+
+
+# extensions, 
+dn: ou=extensions,dc=myDomain,dc=myDomainExt
+ou: extensions
+objectClass: top
+objectClass: organizationalUnit
+
+# Extension 100 Priority 1 in context ldaptest
+dn: cn=100-1,ou=extensions,dc=myDomain,dc=myDomainExt
+AstExtensionApplication: NoOp
+AstExtensionApplicationData: TEST LDAP
+objectClass: top
+objectClass: AstExtension
+AstExtensionExten: 100
+AstExtensionContext: ldaptest
+cn: 100-1
+AstExtensionPriority: 1
+
+# Extension 100 Priority 1 in context ldaptest
+dn: cn=100-2,ou=extensions,dc=myDomain,dc=myDomainExt
+objectClass: top
+objectClass: AstExtension
+AstExtensionExten: 100
+AstExtensionContext: ldaptest
+cn: 100-2
+AstExtensionPriority: 2
+AstExtensionApplication: hangup
+