Add compliant height, using ZINT_COMPLIANT_HEIGHT flag for back-compatibility

Rename barcode funcs to same as BARCODE_XXX name
library: barcode funcs array for dispatch, used for ZBarcode_ValidID() also
general: change is_sane() comparison to nonzero from ZINT_ERROR_INVALID_OPTION
MAILMARK: fuller error messages
CODABAR: add option to show check character in HRT
zint.h: use 0xNNNN for OR-able defines
GUI: add guard descent height reset button, add Zint version to window title,
  static get_zint_version() method, use QStringLiteral (QSL shorthand),
  use SIGNAL(toggled()), add errtxt "popup" and status bar, add icons,
  add saveAs shortcut, add main menu, context menus and actions, add help,
  reset_view() -> reset_colours(), add copy to clipboard as EMF/GIF/PNG/TIF,
  lessen triggering of update_preview(), shorten names of getters/setters,
  simplify/shorten some update_preview() logic in switch,
  CODEONE disable structapp for Version S
qzint.cpp: add on_errored signal, add missing getters, add test

frontend_qt/grpCodeOne.ui

@@ -28,7 +28,11 @@
         <string>Symbol Si&amp;ze:</string>
        </property>
        <property name="toolTip">
-        <string>Set size (version) of symbol</string>
+        <string>Set size (H x W) of symbol
+Versions A to H have fixed heights and
+fixed widths
+Versions S and T have fixed heights but
+variable widths</string>
        </property>
        <property name="alignment">
         <set>Qt::AlignLeading|Qt::AlignLeft|Qt::AlignVCenter</set>
@@ -40,8 +44,15 @@
      </item>
      <item row="0" column="1">
       <widget class="QComboBox" name="cmbC1Size">
+       <property name="maxVisibleItems">
+        <number>11</number>
+       </property>
        <property name="toolTip">
-        <string>Set size (version) of symbol</string>
+        <string>Set size (H x W) of symbol
+Versions A to H have fixed heights and
+fixed widths
+Versions S and T have fixed heights but
+variable widths</string>
        </property>
        <item>
         <property name="text">
@@ -149,7 +160,8 @@ formatted with Application Identifiers (AIs)
      </property>
      <property name="toolTip">
       <string>Code One supports Structured Append of up to
-128 symbols</string>
+128 symbols (not available for Version S)
+(ignored if disabled)</string>
      </property>
      <layout class="QGridLayout" name="gridLayoutC1StructApp">
       <item row="0" column="0">
@@ -178,7 +190,7 @@ containing a total of this number of symbols
 Value ranges from 1 (Disabled) to 128</string>
         </property>
         <property name="specialValueText">
-         <string>1 (Disabled)</string>
+         <string> 1 (Disabled)</string>
         </property>
         <property name="minimum">
          <number>1</number>