Add link to FAQ

Closes #24

app/src/main/res/menu/list_habits_menu.xml

@@ -34,6 +34,12 @@
         android:title="@string/action_settings"
         app:showAsAction="never"/>
 
+    <item
+        android:id="@+id/action_faq"
+        android:orderInCategory="100"
+        android:title="@string/help"
+        app:showAsAction="never"/>
+
     <item
         android:id="@+id/action_about"
         android:orderInCategory="100"

app/src/main/res/values/constants.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2016 Álinson Santos Xavier <isoron@gmail.com>
+  ~
+  ~ This file is part of Loop Habit Tracker.
+  ~
+  ~ Loop Habit Tracker is free software: you can redistribute it and/or modify
+  ~ it under the terms of the GNU General Public License as published by the
+  ~ Free Software Foundation, either version 3 of the License, or (at your
+  ~ option) any later version.
+  ~
+  ~ Loop Habit Tracker is distributed in the hope that it will be useful, but
+  ~ WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+  ~ or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+  ~ more details.
+  ~
+  ~ You should have received a copy of the GNU General Public License along
+  ~ with this program. If not, see <http://www.gnu.org/licenses/>.
+  -->
+<resources>
+    <string name="helpURL">https://isoron.github.io/uhabits/faq.html</string>
+    <string name="playStoreURL">market://details?id=org.isoron.uhabits</string>
+    <string name="feedbackURL" formatted="false">mailto:isoron+habits@gmail.com?subject=Feedback%20about%20Loop%20Habit%20Tracker</string>
+    <string name="sourceCodeURL">https://github.com/iSoron/uhabits</string>
+</resources>

app/src/main/res/values/strings.xml

@@ -137,4 +137,5 @@
     <string name="two_times_per_week">2 times per week</string>
     <string name="five_times_per_week">5 times per week</string>
     <string name="custom_frequency">Custom …</string>
+    <string name="help">Help &amp; FAQ</string>
 </resources>

app/src/main/res/xml/preferences.xml

@@ -44,6 +44,12 @@
         android:key="pref_key_links"
         android:title="@string/links">
 
+        <Preference android:title="@string/help">
+            <intent
+                android:action="android.intent.action.VIEW"
+                android:data="@string/helpURL"/>
+        </Preference>
+
         <Preference android:title="@string/about">
             <intent
                 android:action="android.intent.action.VIEW"