Calculator: Update italian translation

Change-Id: Ide18f04b9f7b5d6a83ca91997ca5034703c98406
Move the window background to the activity theme

This has several advantages:

- Reduces overdraw and improves performance especially on weaker and
  older devices

- Centralizes the background attribute out of the layout files

- Shows the proper solid background when the calculator is launching

Change-Id: Id3a4f7499a8bfc50f6b0ff8307d9d420861e0858
Merge "Move the window background to the activity theme" into cm-10.1
Merge remote-tracking branch 'cm/cm-10.1' into jb-4.2.2_r1
Added translation for New Features Part 3

Change-Id: I57842703e49464fa663e3fe2b2d7b1dd97dbc1b3