Messages Alignment

Alignment for uplink/datalink messages:

e.g.

 32bits -->  [     8    ][    16    ][    24    ][    32    ]

CORRECT

 PAYLOAD = { [   char   ][        uint16        ][   int8   ]
             [                    uint32                    ]
             [   uint8  ][ uint8[0] ][ uint8[1] ][ uint8[2] ]
             [ uint8[3] ][        int16         ][  length  ]
             [       uint16[](1)    ][       uint16[](2)    ]
             [       uint16[](3)    ]...

INCORRECT

 PAYLOAD = { [   char   ][        uint16        ][        ...
             ...          uint32                ][   int8   ]