Settings: PL Translations, fixes and improvements.

Small fixes.

Change-Id: I1fc4f26334e89578b1ed6bbb9d61accf4e9bb15e
Settings: updated it translation

Change-Id: I4051a10c56ca25ea1749ca60231e100405f77f3a
Settings: Volume panel background color && transparency [1/2]

Allow user to specify background color and transparency level
    for volume panel.

PS: make "TRDS default" summary value a resource so
        it can be translated.

Change-Id: Ic788b4ccf1826075a600e53bc6a7c3c8bda50685
Merge "Settings: updated it translation" into kk4.4