Adding support to multiple screens.

Nowadays, MM doesn't supports multiple screens (e.g. tablets) in a great way.
We starting to add this by replacing activities to fragments.

Some references:

Supporting Multiple Screens
http://developer.android.com/guide/practices/screens_support.html

Designing for Multiple Screens
http://developer.android.com/training/multiscreen/index.html

Fragments:
http://developer.android.com/guide/components/fragments.html
Migrated some activities to fragments

For now, we have migrated the main screen, the author list and
partially the playlist list.

This was made following this post blog:
http://suelengc.com.br/blog/?p=360
Added a default case on switch main menu
Now, the Playlist button main menu works.
Added some screenshots
Resolved the "ghost" fragment (Playlist) problem.

But the problem yet appears when we changed the device orientation
Converted AudioPlayerActivity to AudioPlayerFragment
Updated AudioSelectActivity to AudioSelectFragment

Updated some methods onCreateOptionsMenu(Menu) (Activity class) to
onCreateOptionsMenu(Menu, MenuInflater) (Fragment class) , too.
Updated ShareListActivity to ShareListFragment
Some fix
Fixed the button Artists workflow in larges screen

Before, when we navigate in the button Artists workflow,
and the Back button was clicked, the app is closed.
Now, when the button is clicked, the fragment showed back to
previous one.
Updated PlayListEditorActivity to PlayListEditorFragment
Updated MusicSelectActivity to usicSelectFragment
Using AudioPlayerFragment instead of AudioPlayerActivity in PlayListEditorFragment
Merge pull request #16 from adorilson/fragmentation

Using fragments instead of activities