Add icon field boolean field type

(cherry picked from commit 0295d9c)

images/images.qrc

@@ -728,6 +728,7 @@
         <file>themes/default/mIconAllRings.svg</file>
         <file>themes/default/mIconExteriorRing.svg</file>
         <file>themes/default/mIconInteriorRings.svg</file>
+        <file>themes/default/mIconFieldBool.svg</file>
     </qresource>
     <qresource prefix="/images/tips">
         <file alias="symbol_levels.png">qgis_tips/symbol_levels.png</file>

images/themes/default/mIconFieldBool.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" height="16" width="16"><path d="M4.182 4.765v1.288H5.93l-.017.93H4.165l.017 2.434c.002.21.05.362.152.455.104.09.275.134.513.134H5.93v.947H4.759c-.707 0-1.186-.112-1.435-.336-.25-.228-.37-.647-.375-1.259l-.017-2.375H1.728l.017-.93H2.95V4.765z" font-weight="700" font-family="DejaVu Sans Mono" letter-spacing="0" word-spacing="0" fill="#555" stroke="#555" stroke-width=".095"/><path d="M9.756 4.533h.93l-3.308 7.083h-.93z" font-weight="700" font-family="DejaVu Sans Mono" letter-spacing="0" word-spacing="0" fill="#555"/><path d="M13.19 5.704v.362h.8l-.018.93h-.798l.017 3.97h-1.14l-.017-3.97h-1.006l.017-.93h1.006v-.278c0-.567.11-.96.331-1.178.222-.22.632-.329 1.232-.329h.952v.947h-.921c-.174 0-.292.034-.356.101-.06.068-.093.193-.098.375z" font-weight="700" font-family="DejaVu Sans Mono" letter-spacing="0" word-spacing="0" fill="#555" stroke="#555" stroke-width=".095"/></svg>

src/core/qgsfields.cpp

@@ -258,6 +258,9 @@ QIcon QgsFields::iconForField( int fieldIdx ) const
 {
   switch ( d->fields.at( fieldIdx ).field.type() )
   {
+    case QVariant::Bool:
+      return QgsApplication::getThemeIcon( "/mIconFieldBool.svg" );
+
     case QVariant::Int:
     case QVariant::UInt:
     case QVariant::LongLong: