PLCgen: IO table file: allow more PLC data types for S7

The PLCgen in ESCET 6.0 allows for S7-400 doesn't allow to use the following SCL data types in the IO table file:

• BYTE
• CHAR
• WORD
• DWORD
• TIME
• Date
• TIME_OF_DAY
• DATE_AND_TIME

Usually this PLC data types are not needed (see the discussion in #1062 (closed)). However, there are situation when the use of these types is recommended of even necessary. For example when using SIMIT.

I propose to allow to use these data types in the PLCgen. However I also propose to give a warning when using these data types.

Addressees: #679, #1062 (closed), #1107, #1109

ERROR: Type "BYTE" contained in the 'PLC type' field is not a usable type for input/output (second field at line 2 of I/O table file "io_func_func.csv").
ERROR: Type "CHAR" contained in the 'PLC type' field is not a usable type for input/output (second field at line 2 of I/O table file "io_func_func.csv").
ERROR: Type "WORD" contained in the 'PLC type' field is not a usable type for input/output (second field at line 2 of I/O table file "io_func_func.csv").
ERROR: Type "DWORD" contained in the 'PLC type' field is not a usable type for input/output (second field at line 2 of I/O table file "io_func_func.csv").
ERROR: Type "TIME" contained in the 'PLC type' field is not a usable type for input/output (second field at line 1 of I/O table file "io_real.csv").
ERROR: Type "Date" contained in the 'PLC type' field is not a usable type for input/output (second field at line 1 of I/O table file "io_real.csv").
ERROR: Type "TIME_OF_DAY" contained in the 'PLC type' field is not a usable type for input/output (second field at line 1 of I/O table file "io_real.csv").
ERROR: Type "DATE_AND_TIME" contained in the 'PLC type' field is not a usable type for input/output (second field at line 1 of I/O table file "io_real.csv").