Added support to directly connect also to Microsoft SQL Server database.

Fixed direct connection to always use the same query as of UNION query SQL injection (= one query with multiple columns/entries output).
Minor fixes to Firebird/Access/SQLite connectors to use connector's execute()/fetchall() as wrapper for third-party libraries' methods.
Forced conf.timeout to 10 seconds when directly connecting to database.
Slightly improved regular expression to parse -d parameter.
Added import check for all connectors' third-party libraries.
Code refactoring:
* Moved conf.direct request to direct() function in lib/request/direct.py (code reused where needed).
* Back-delegated to generic connector close() and other methods.

plugins/dbms/mssqlserver/fingerprint.py

@@ -97,8 +97,13 @@ class Fingerprint(GenericFingerprint):
         infoMsg = "testing Microsoft SQL Server"
         logger.info(infoMsg)
 
-        payload = agent.fullPayload(" AND LEN(@@VERSION)=LEN(@@VERSION)")
-        result  = Request.queryPage(payload)
+        # NOTE: SELECT LEN(@@VERSION)=LEN(@@VERSION) FROM DUAL does not work connecting
+        # directly to the Microsoft SQL Server database
+        if conf.direct:
+            result = True
+        else:
+            payload = agent.fullPayload(" AND LEN(@@VERSION)=LEN(@@VERSION)")
+            result  = Request.queryPage(payload)
 
         if result:
             infoMsg = "confirming Microsoft SQL Server"