[2/3] Flip to mute/decline incoming call

Add user configurable options to flip the phone in order to
0: mute call
1: decline call
2: do nothing (default)

[2/3] 翻转以 静音/挂断 来电

添加用户可配置的选项来翻转手机以
0: 静音来电
1: 挂断来电
2: 啥也不干 (默认)

[1/3] in platform_packages_apps_InCallUI
[3/3] in platform_frameworks_base