project: Add configurable gettext domain

The gettext domain is hardcoded in the gschema file. It has been
changed so its now configurable and its possible to change it
via build files.

data/org.gnome.calendar.gschema.xml.in

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<schemalist gettext-domain="@GETTEXT_PACKAGE@">
+    <schema id="org.gnome.calendar" path="/org/gnome/calendar/">
+        <key name="window-maximized" type="b">
+            <default>true</default>
+            <summary>Window maximized</summary>
+            <description>Window maximized state</description>
+        </key>
+        <key name="window-size" type="(ii)">
+            <default>(768, 600)</default>
+            <summary>Window size</summary>
+            <description>Window size (width and height).</description>
+        </key>
+        <key name="window-position" type="(ii)">
+            <default>(-1, -1)</default>
+            <summary>Window position</summary>
+            <description>Window position (x and y).</description>
+        </key>
+        <key name="active-view" enum="org.gnome.calendar.GcalWindowView">
+            <default>'month'</default>
+            <summary>Type of the active view</summary>
+            <description>Type of the active window view, default value is: monthly view</description>
+        </key>
+        <key name="weather-settings" type="(bbsmv)">
+            <default>(true, true, '', nothing)</default>
+            <summary>Weather Service Configuration</summary>
+            <description>Whether weather reports are shown, automatic locations are used and a location-name</description>
+        </key>
+    </schema>
+</schemalist>