Move subsurface-core to core and qt-mobile to mobile-widgets

Having subsurface-core as a directory name really messes with
autocomplete and is obviously redundant. Simmilarly, qt-mobile caused an
autocomplete conflict and also was inconsistent with the desktop-widget
name for the directory containing the "other" UI.

And while cleaning up the resulting change in the path name for include
files, I decided to clean up those even more to make them consistent
overall.

This could have been handled in more commits, but since this requires a
make clean before the build, it seemed more sensible to do it all in one.

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

mobile-widgets/qml/Preferences.qml

@@ -0,0 +1,74 @@
+import QtQuick 2.3
+import QtQuick.Controls 1.2
+import QtQuick.Window 2.2
+import QtQuick.Dialogs 1.2
+import QtQuick.Layouts 1.1
+import org.kde.kirigami 1.0 as Kirigami
+import org.subsurfacedivelog.mobile 1.0
+
+Kirigami.Page {
+
+	title: "Preferences"
+	mainAction: Action {
+		text: "Save"
+		iconName: "document-save"
+		onTriggered: {
+			manager.distanceThreshold = distanceThreshold.text
+			manager.timeThreshold = timeThreshold.text
+			manager.savePreferences()
+			stackView.pop()
+		}
+	}
+
+	GridLayout {
+
+		signal accept
+
+		columns: 2
+		width: parent.width - Kirigami.Units.gridUnit
+		anchors {
+			fill: parent
+			margins: Kirigami.Units.gridUnit / 2
+		}
+
+		Kirigami.Heading {
+			text: "Preferences"
+			Layout.bottomMargin: Kirigami.Units.largeSpacing / 2
+			Layout.columnSpan: 2
+		}
+
+		Kirigami.Heading {
+			text: "Subsurface GPS data webservice"
+			level: 3
+			Layout.topMargin: Kirigami.Units.largeSpacing
+			Layout.bottomMargin: Kirigami.Units.largeSpacing / 2
+			Layout.columnSpan: 2
+		}
+
+		Kirigami.Label {
+			text: "Distance threshold (meters)"
+			Layout.alignment: Qt.AlignRight
+		}
+
+		TextField {
+			id: distanceThreshold
+			text: manager.distanceThreshold
+			Layout.fillWidth: true
+		}
+
+		Kirigami.Label {
+			text: "Time threshold (minutes)"
+			Layout.alignment: Qt.AlignRight
+		}
+
+		TextField {
+			id: timeThreshold
+			text: manager.timeThreshold
+			Layout.fillWidth: true
+		}
+
+		Item {
+			Layout.fillHeight: true
+		}
+	}
+}