Fix UI issues and warning

Commit e219bc70f8 ("Refactor dctype -> divemode") introduced a few issues.
For one thing it causes a warning about incorrect use of zorder - I don't see
why this would be needed here, so I simply removed it.

Secondly, it adds a new, automatically named layout element that therefore gets
handled by our "consistent margin" code which creates a messy layout for the
Dive Notes tab. This patch gives that horizontal layout a useful name and adds
it to the list of "zero margin" layouts.  Signed-off-by: Dirk Hohndel
<dirk@hohndel.org>

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/maintab.ui

@@ -22,9 +22,7 @@
      <number>0</number>
     </property>
     <item row="2" column="1">
-     <widget class="KMessageWidget" name="diveNotesMessage" native="true">
+     <widget class="KMessageWidget" name="diveNotesMessage" native="true"/>
-      <zorder>scrollArea</zorder>
-     </widget>
     </item>
     <item row="3" column="1">
      <widget class="QScrollArea" name="scrollArea">
@@ -374,7 +372,7 @@
          </layout>
         </item>
         <item row="7" column="0" colspan="3">
-         <layout class="QHBoxLayout" name="horizontalLayout_2">
+         <layout class="QHBoxLayout" name="coordinatesDiveTypeLayout">
           <item>
            <widget class="QLineEdit" name="coordinates">
             <property name="readOnly">

qt-ui/mainwindow.cpp

@@ -127,6 +127,7 @@ MainWindow::MainWindow() : QMainWindow(),
 	QMargins zeroMargins(0, 0, 0, 0);
 	QList<QString> noMarginList;
 	noMarginList << "notesAndSocialNetworksLayout" <<
+			"coordinatesDiveTypeLayout" <<
 			"mainTabOuterLayout" <<
 			"ratingVisibilityWidgets" <<
 			"temperatureLabels" <<