Fix bootzip. Install signapk to sign the package and some cleanup

Change-Id: Ife5b74e4643ab757e94deba01d384aa2674cddda
convert bash to python for the bootzip creator script

PS4: added fstab check and some cleanup

Change-Id: Icff7d5ac7e2b442f1ffe5c4c11e02aa0b18333f3

Conflicts:
	core/Makefile