InCallUI: Disable Back button on Non-intursive InCall Card

Fix for jira issue http://jira.omnirom.org/browse/OMNI-296

PS2 to PS5: code cleanup

PS6: Remove Jira issue url from code

Change-Id: I257daccbb175265e2430f1b0b30c9175cb4b1981
In-Call UI from blue to white

we changed the default dialpad from blue to white
but forgot this in call dialpad,
make it white ui to be consistent

Change-Id: Ie715340d69adb1514e5f1d5bb159b8c42494015a
trds: cleanup!

drawables not needed anymore after this
https://gerrit.slimroms.net/#/c/1675/

Change-Id: Ic237384fe60f23dd2b953da5d7be36c9a4c1191d