Use support-v4 and appcompat-v7 version 21.0.0
Update search action bar icon
Revert "Update drawables for ic_action_wikipedia"

This reverts commit 0272f08310cc635c7ee622ba4872bc12f7480aae.
Add xxxhdpi drawable for wikipedia action bar icon
Rename ic_action_wikipedia to ic_menu_wikipedia
PropertiesActivity: Fix action bar home button
AboutActivity: Add action bar using android.support.v7.widget.Toolbar
PropertiesActivity: Change PagerTabStrip colors
Use appcompat-v7's drawable for action bar search icon
Fix drawable name in properties_action_menu.xml
Add xxxhdpi drawable for ic_launcher
Rename ic_launcher to ic_launcher_periodic_table
AboutActivity: Fix navigation icon vertical alignment
MainActivity: Use TabsAdapter
MainActivity: Move remaining ElementsFragment's code into ElementsFragment
MainActivity: Do not handle configuration changes on our own
PropertiesActivity: Use PagesAdapter
PropertiesActivity: Change EXTRA_ATOMIC_NUMBER value
PropertiesActivity: Rename Details fragment to Properties
Fix several problems with types conversion