Release preparation : threaded version (update device for a channel every second while gathering channel data every 500ms)

- length check when updating spectrum Attributes
- minor change in waveform.cpp file.

minor change

- SocketLecroy file splitted for Win32 and Linux like platforms
- Bugs fixed in SocketLecroy

calculation of offset of the begining of the struct, which contains the context of the waveform acquisition, in the received block data.