AUSPOST: support Null FCC (DPID all zeroes); TODO: BWIPP support

CODE128: properly fix not switching before FNC1 in 2nd position
  after alpha (commit [7b0767])
PLANET/KIX: adapt POSTNET to cater for both
general: use static strings to save a few bytes (start/stop in
  particular); various other code fiddles
postal: move tables into funcs

docs/manual.html

@@ -6086,7 +6086,8 @@ alt="zint -b AUSPOST --compliantheight -d "96184209"" />
 Control Code (FCC) is added by Zint and should not be included in the
 input data. Reed-Solomon error correction data is generated by Zint.
 Encoding behaviour is determined by the length of the input data
-according to the formula shown in the following table.</p>
+according to the formula shown in the following table. The first 8
+digits is the DPID.</p>
 <table id="tbl:auspost_input_formats" style="width:86%;">
 <caption><span class="table-label">Table 23:</span> Australia Post Input
 Formats</caption>
@@ -6103,7 +6104,7 @@ Formats</caption>
 <th style="text-align: left;">Required Input Format</th>
 <th>Symbol Length</th>
 <th>FCC</th>
-<th style="text-align: left;">Encoding Table</th>
+<th>Encoding Table(s)</th>
 </tr>
 </thead>
 <tbody>
@@ -6112,38 +6113,41 @@ Formats</caption>
 <td style="text-align: left;"><code>99999999</code></td>
 <td>37-bar</td>
 <td>11</td>
-<td style="text-align: left;">None</td>
+<td>N</td>
 </tr>
 <tr>
 <td style="text-align: left;">13</td>
 <td style="text-align: left;"><code>99999999AAAAA</code></td>
 <td>52-bar</td>
 <td>59</td>
-<td style="text-align: left;">C</td>
+<td>N and C</td>
 </tr>
 <tr>
 <td style="text-align: left;">16</td>
 <td style="text-align: left;"><code>9999999999999999</code></td>
 <td>52-bar</td>
 <td>59</td>
-<td style="text-align: left;">N</td>
+<td>N</td>
 </tr>
 <tr>
 <td style="text-align: left;">18</td>
 <td style="text-align: left;"><code>99999999AAAAAAAAAA</code></td>
 <td>67-bar</td>
 <td>62</td>
-<td style="text-align: left;">C</td>
+<td>N and C</td>
 </tr>
 <tr>
 <td style="text-align: left;">23</td>
 <td style="text-align: left;"><code>99999999999999999999999</code></td>
 <td>67-bar</td>
 <td>62</td>
-<td style="text-align: left;">N</td>
+<td>N</td>
 </tr>
 </tbody>
 </table>
+<p>The special Null FCC 00, non-machine readable and intended for
+customer use only, is used (all input lengths) if the DPID is all
+zeroes.</p>
 <h4 id="reply-paid-barcode">6.5.1.2 Reply Paid Barcode</h4>
 <p>A Reply Paid version of the Australia Post 4-State Barcode (FCC 45)
 which requires an 8-digit DPID input.</p>