Added missing FloatingWidgetTitleBar.cpp and missing stylesheet file for linux

src/stylesheets/default_linux.css

@@ -0,0 +1,96 @@
+
+/*
+ * Default style sheet on Windows Platforms
+ * Note: Always use CSS-classes with and without "ads--" namespace to support Qt4 & Qt5
+ */
+
+ads--CDockContainerWidget
+{
+    background: palette(dark);
+}
+
+ads--CDockContainerWidget QSplitter::handle
+{
+    background: palette(dark);
+}
+
+ads--CDockAreaWidget
+{
+    background: palette(window);
+    border: 1px solid white;
+}
+
+ads--CDockAreaWidget #tabsMenuButton::menu-indicator
+{
+    image: none;
+}
+
+
+ads--CDockWidgetTab
+{
+    background: palette(window);
+    border-color: palette(light);
+    border-style: solid;
+    border-width: 0 1px 0 0;
+    padding: 0 0px;
+}
+
+ads--CDockWidgetTab[activeTab="true"]
+{
+    background: qlineargradient(spread:pad, x1:0, y1:0, x2:0, y2:0.5, stop:0 palette(window), stop:1 palette(light));
+    /*background: palette(highlight);*/
+}
+
+ads--CDockWidgetTab QLabel
+{
+    color: palette(dark);
+}
+
+ads--CDockWidgetTab[activeTab="true"] QLabel
+{
+    color: palette(foreground);
+}
+
+ads--CDockWidget
+{
+    background: palette(light);
+    border-color: palette(light);
+    border-style: solid;
+    border-width: 1px 0 0 0;
+}
+
+#tabsMenuButton,
+#closeButton,
+#undockButton
+{
+	padding: 0px -2px;
+}
+
+
+QScrollArea#dockWidgetScrollArea
+{
+	padding: 0px;
+	border: none;
+}
+
+
+#tabCloseButton
+{
+        margin-top: 2px;
+        background: none;
+        border: none;
+        padding: 0px -2px;
+}
+
+#tabCloseButton:hover
+{
+        border: 1px solid rgba(0, 0, 0, 32);
+        background: rgba(0, 0, 0, 16);
+}
+
+#tabCloseButton:pressed
+{
+        background: rgba(0, 0, 0, 32);
+}
+
+