Improved autotools files.

Moved all the style data to a theme directory ala gnome-shell.
Added close-window.svg image.
Added gcal-marshalers.list and rules to Makefile.am to generate the correct
source and header.

Note: The absence of this changes about the marshallers generation was
making imposible to compile the changes about GcalView API. This will complete
that commit.

data/theme/gtk-styles.css

@@ -0,0 +1,117 @@
+/*******
+ * OSD *
+ *******/
+@define-color osd_highlight #ffffff;
+@define-color osd_base #212526;
+
+@define-color osd_fg #ededed;
+@define-color osd_bg alpha(@osd_base, 0.80);
+
+@define-color osd_toolbar_bg_a alpha(@osd_base, 0.80);
+@define-color osd_toolbar_bg_b alpha(#101010, 0.80);
+@define-color osd_toolbar_bg_c alpha(shade(@osd_base, 1.02), 0.80);
+
+GtkClutterOffscreen.contents {
+  background-color: #fafafa;
+  background-image: none;
+}
+
+GtkClutterOffscreen.contents .frame {
+  border: 0;
+  border-top: 1px lightgrey solid;
+  border-radius: 0px;
+
+  margin: 0;
+}
+
+.main-toolbar {
+  padding-top: 12px;
+  padding-bottom: 12px;
+}
+
+.main-toolbar .button {
+  padding: 2px;
+}
+
+.osd.view {
+  color: @osd_fg;
+  background-color: transparent;
+}
+
+.calendar-view header {
+  font: bold 12;
+  padding: 12px;
+}
+
+.calendar-view {
+  padding: 6px;
+  font: 10;
+}
+
+
+.calendar-view:selected {
+  color: #0C73E5;
+  background-color: shade (#fff, 0.5);
+  font: bold;
+}
+
+.event {
+  border-radius: 0;
+  padding-top: 3px;
+  padding-left: 6px;
+  padding-bottom: 3px;
+  padding-right: 6px;
+  font: 9;
+}
+
+.event-details .frame {
+  border-style: solid;
+  border-color: @borders;
+  border-width: 0.5px;
+  border-radius: 0;
+}
+
+.scrollbar.slider {
+  background-color: alpha (@scrollbar_slider, 0.5);
+  border: #6e6e6e 1px solid;
+}
+.scrollbar.trough {
+  background-color: transparent;
+  background-image: none;
+}
+
+.entry {
+  border-radius: 0;
+}
+
+GtkClutterOffscreen.overlay {
+  background-color: transparent;
+  background-image: none;
+}
+
+GtkClutterOffscreen.overlay .frame {
+  padding: 12px;
+  margin: 12px;
+}
+
+GtkClutterOffscreen.overlay .frame * {
+  color: @theme_fg_color;
+}
+
+GtkOverlay > GtkButton {
+   padding-top: 0px;
+   padding-right: 0px;
+   background-color: transparent;
+   background-image: none;
+   border: 0;
+}
+
+.new-event-view {
+   padding: 18px;
+   border-radius: 3px;
+   border: darkblue 1px solid;
+  color: @theme_fg_color;
+   background-color: @theme_bg_color;
+   -GcalArrowContainer-arrow-size: 12px;
+   -GcalArrowContainer-shadow-span: 6px;
+}