frontends, jp, templates: added XHTMLBox widget:

for jp, the XHTML is rendered for now using markdown.

sat_frontends/jp/xmlui_manager.py

@@ -238,6 +238,18 @@ class TextBoxWidget(xmlui_base.TextWidget, StringWidget):
     type = u"textbox"
 
 
+class XHTMLBoxWidget(xmlui_base.XHTMLBoxWidget, StringWidget):
+    type = u"xhtmlbox"
+
+    def show(self):
+        # FIXME: we use bridge in a blocking way as permitted by python-dbus
+        #        this only for now to make it simpler, it must be refactored
+        #        to use async when jp will be fully async (expected for 0.8)
+        self.value = self.host.bridge.syntaxConvert(
+            self.value, C.SYNTAX_XHTML, "markdown", False, self.host.profile)
+        super(XHTMLBoxWidget, self).show()
+
+
 class ListWidget(xmlui_base.ListWidget, OptionsWidget):
     type = u"list"
     # TODO: handle flags, notably multi