Improve handling of SQL warnings

[rikedyp]

Use SQA.GetWarning to get the actual content of warnings and print to session.

    ∇ msg←Catch msg;en;w
      en←⊃msg
      :If 0<en       ⍝ Server error if database operation fails
          {}SQA.Close cur
          :If 2006=2 2⊃msg   ⍝ SQL server has gone away
              Debug'> SQL SERVER WAS AWAY FOR QUERY: ',⍕⎕TS
              SQA.Close db
              Connect ##.GetEnv¨'SQL_DATABASE' 'SQL_PASSWORD' 'SQL_USER'
          :Else
              (3⊃msg)⎕SIGNAL 500
          :EndIf
      :ElseIf 0>en
          ⎕←msg←2 1⊃SQA.GetWarning cur   ⍝ Print and pass on warning
      :EndIf
    ∇