Wireless sensor node - code fixes (3 - redux)

In my last post I realised a few things which needed to be fixed. These are now done!

• My RX code no longer checks the range of the node ID and msg number which by definition were always in range.
• The Manchester RX code now checks for low/high frequency interference during the data reception.
• I have fixed a bug in the Manchester RX code which didn't properly check the timings of the pre-amble.

These changes can be seen here.