Retrospective commit message correction + housekeeping + minor updates.

The previous commit message omitted some of the major changes
between Rev.L and Rev.M.
The major changes as of the previous commit (initial commit of rev.M) were:
- Accelerometer added (ADXL362).
- Battery 'Fuel Gauge' IC (MAX17043G+U) updated to smaller (MAX17048G+).
- Backlight LED switched directly by EFM32, (i.e. MOSFET switch removed).

Changes introduced as of *this* commit:
- Debug Interface 'P7' relabelled 'P6', to reflect actual total pin count.
- Piezoelectric diaphragm (PED) connections (pads) labelled 'PADx',
  relabelled 'SPx' to better reflect the Spring Pin component fitted.
- PED SP module (PCB footprint) - outline now depicted in 'Dwgs.User' layer.
- Component 'PIEZO_DIAPHRAGM-DUMMY' added to enable inclusion of the PED
  in the Bill of Materials (BOM), without generating a physical board-mounted
  component in Pcbnew.
- Schematic layout - minor tidying.
- OTM-02_bom-colour_coded.pdf - added. A google docs based, colour-coded BOM:
  https://docs.google.com/spreadsheet/ccc?key=0AiBBK0ta6UF0dHBZZUZtNGNDcU9SalJwMnNUR1ctb2c&usp=sharing
- OTM-02_assy_drawing-colour_coded.pdf added. (Begins life as SVG plot in Pcbnew,
  further edited and coloured in Inkscape.
- OTM-02_assy_drawing.pdf - removed. (Due poor quality.)
- OTM-02.dcm documentation file added.

NB: All changes as of this commit are compatible with the first batch of
Rev.M PCBs manufactured.