Sign final packages with a different key if requested

...and throw it into recovery builds as well

Change-Id: Ic96d4d49d821cb03d5318e3e9ad93d02fb92573e
add echochanged function

ignore bash/vim/nano config files in echochanged function, change output format

Change-Id: Ifb298ba430f2c9f4423716d9fd365664ba65adb6
add repolog function

repolog: jellybean -> cm-10.1

Change-Id: I083e63fc72c5c152207196be1302f70cf430fe03
hardcode build user and host

Change-Id: I1b8132f11bb249dd7a950662c02898da9b4584c0
Update echochanged function

Change-Id: I667f8bfe839f18d8d9e06981cfd899d3da3a6f27
Save repolog log to $OUT

Change-Id: Iaaf1d7418923850c75d3a82e726d0206a260ee1c