week-header: created the basic skeleton of the week-header

Created the .h, .c and .ui file of week header. Also made changes in the Makefile.am for it to get built.

data/Makefile.am

@@ -61,6 +61,7 @@ EXTRA_DIST=                     \
   ui/search-view.ui             \
   ui/source-dialog.ui           \
   ui/time-selector.ui           \
+  ui/week-header.ui             \
   ui/window.ui                  \
   ui/year-view.ui               \
   theme/gtk-styles.css          \

data/calendar.gresource.xml

@@ -12,6 +12,7 @@
     <file alias="search-view.ui" compressed="true" preprocess="xml-stripblanks">ui/search-view.ui</file>
     <file alias="source-dialog.ui" compressed="true" preprocess="xml-stripblanks">ui/source-dialog.ui</file>
     <file alias="time-selector.ui" compressed="true" preprocess="xml-stripblanks">ui/time-selector.ui</file>
+    <file alias="week-header.ui" compressed="true" preprocess="xml-stripblanks">ui/week-header.ui</file>
     <file alias="window.ui" compressed="true" preprocess="xml-stripblanks">ui/window.ui</file>
     <file alias="year-view.ui" compressed="true" preprocess="xml-stripblanks">ui/year-view.ui</file>
     <file alias="gtk-styles.css" compressed="true">theme/gtk-styles.css</file>

data/ui/week-header.ui

@@ -0,0 +1,29 @@
+<?xml version="1.0"?>
+<interface>
+  <template class="GcalWeekHeader" parent="GtkScrolledWindow">
+    <property name="visible">True</property>
+    <property name="shadow_type">out</property>
+    <property name="hexpand">True</property>
+    <child>
+      <object class="GtkViewport">
+        <property name="visible">True</property>
+        <child>
+          <object class="GtkOverlay">
+            <property name="visible">True</property>
+            <child>
+              <object class="GtkDrawingArea">
+                <property name="visible">True</property>
+                <signal name="draw" handler="gcal_week_header_draw" object="GcalWeekHeader" swapped="yes"/>
+              </object>
+            </child>
+            <child type="overlay">
+              <object class="GtkGrid" id="grid">
+                <property name="visible">True</property>
+              </object>
+            </child>
+          </object>
+        </child>
+      </object>
+    </child>
+  </template>
+</interface>