Adds material-style dialogs, and also allow to have an ActionBar even on PreferenceActivity

This library is based on some other libraries, to support the next features:

• alert dialogs, with a similar style of Material-Design.
• PreferenceActivity, with support of an ActionBar (which is actually a toolbar that looks like an ActionBar)

I made it since the current version of the support library doesn't have any of those things. I've asked about it on StackOverflow (here and here), but what I got wasn't enough to support what I needed.

This library needs:

• API 8 and above.
• AppCompat v4 and v7.

That's it.

It doesn't style the preferences, and since it's heavily based on this library, it has the same functionality and style for the dialogs. However, I've cleaned the code and removed un-needed files, so it's lighter.

The project consists of some libraries and websites I've looked at :

• AlertDialogPro (for the alert dialogs): https://github.com/fengdai/AlertDialogPro
• ActionBarSherlock (for the shadow below the action bar) : http://actionbarsherlock.com/
• Some code I got from my own app: https://play.google.com/store/apps/details?id=com.lb.app_manager
• The support library of Google, of course: http://android-developers.blogspot.co.il/2014/10/appcompat-v21-material-design-for-pre.html
• This website: https://chris.banes.me/2014/10/17/appcompat-v21/